Class: String

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses: Warning::buffer
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, `::Comparable`
Inherits:	Object
Defined in:	string.c, complex.c, encoding.c, pack.rb, rational.c, string.rb, symbol.c, transcode.c

Overview

A String object has an arbitrary sequence of bytes, typically representing text or binary data. A String object may be created using .new or as literals.

String objects differ from ::Symbol objects in that ::Symbol objects are designed to be used as identifiers, instead of text or data.

You can create a String object explicitly with:

A string literal.
A heredoc literal.

You can convert certain objects to Strings with:

::Method #String.

Some String methods modify self. Typically, a method whose name ends with ! modifies self and returns self; often, a similarly named method (without the !) returns a new string.

In general, if both bang and non-bang versions of a method exist, the bang method mutates and the non-bang method does not. However, a method without a bang can also mutate, such as #replace.

Substitution Methods

These methods perform substitutions:

#sub: One substitution (or none); returns a new string.
#sub!: One substitution (or none); returns self if any changes, nil otherwise.
#gsub: Zero or more substitutions; returns a new string.
#gsub!: Zero or more substitutions; returns self if any changes, nil otherwise.

Each of these methods takes:

A first argument, pattern (String or ::Regexp), that specifies the substring(s) to be replaced.
Either of the following:
- A second argument, replacement (String or Hash), that determines the replacing string.
- A block that will determine the replacing string.

The examples in this section mostly use the #sub and #gsub methods; the principles illustrated apply to all four substitution methods.

Argument pattern

Argument pattern is commonly a regular expression:

s = 'hello'
s.sub(/[aeiou]/, '*') # => "h*llo"
s.gsub(/[aeiou]/, '*') # => "h*ll*"
s.gsub(/[aeiou]/, '')  # => "hll"
s.sub(/ell/, 'al')     # => "halo"
s.gsub(/xyzzy/, '*')   # => "hello"
'THX1138'.gsub(/\d+/, '00') # => "THX00"

When pattern is a string, all its characters are treated as ordinary characters (not as ::Regexp special characters):

'THX1138'.gsub('\d+', '00') # => "THX1138"

String replacement

If replacement is a string, that string determines the replacing string that is substituted for the matched text.

Each of the examples above uses a simple string as the replacing string.

String replacement may contain back-references to the pattern’s captures:

\n (n is a non-negative integer) refers to $n.
\k<name> refers to the named capture name.

See Regexp for details.

Note that within the string replacement, a character combination such as $& is treated as ordinary text, not as a special match variable. However, you may refer to some special match variables using these combinations:

\& and \0 correspond to $&, which contains the complete matched text.
\' corresponds to $', which contains the string after the match.
\` corresponds to $`, which contains the string before the match.
\+ corresponds to $+, which contains the last capture group.

See Regexp for details.

Note that \\ is interpreted as an escape, i.e., a single backslash.

Note also that a string literal consumes backslashes. See Literals for details about string literals.

A back-reference is typically preceded by an additional backslash. For example, if you want to write a back-reference \& in replacement with a double-quoted string literal, you need to write "..\\&..".

If you want to write a non-back-reference string \& in replacement, you need to first escape the backslash to prevent this method from interpreting it as a back-reference, and then you need to escape the backslashes again to prevent a string literal from consuming them: "..\\\\&..".

You may want to use the block form to avoid excessive backslashes.

Hash replacement

If the argument replacement is a hash, and pattern matches one of its keys, the replacing string is the value for that key:

h = {'foo' => 'bar', 'baz' => 'bat'}
'food'.sub('foo', h) # => "bard"

Note that a symbol key does not match:

h = {foo: 'bar', baz: 'bat'}
'food'.sub('foo', h) # => "d"

Block

In the block form, the current match string is passed to the block; the block’s return value becomes the replacing string:

s = '@'
'1234'.gsub(/\d/) { |match| s.succ! } # => "ABCD"

Special match variables such as $1, $2, $`, $&, and $' are set appropriately.

Whitespace in Strings

In the class String, whitespace is defined as a contiguous sequence of characters consisting of any mixture of the following:

NL (null): "\x00", "\u0000".
HT (horizontal tab): "\x09", "\t".
LF (line feed): "\x0a", "\n".
VT (vertical tab): "\x0b", "\v".
FF (form feed): "\x0c", "\f".
CR (carriage return): "\x0d", "\r".
SP (space): "\x20", " ".

Whitespace is relevant for the following methods:

#lstrip, #lstrip!: Strip leading whitespace.
#rstrip, #rstrip!: Strip trailing whitespace.
#strip, #strip!: Strip leading and trailing whitespace.

`String` Slices

A slice of a string is a substring selected by certain criteria.

These instance methods utilize slicing:

#[] (aliased as #slice): Returns a slice copied from self.
#[]=: Mutates self with the slice replaced.
#slice!: Mutates self with the slice removed and returns the removed slice.

Each of the above methods takes arguments that determine the slice to be copied or replaced.

The arguments have several forms. For a string string, the forms are:

string[index]
string[start, length]
string[range]
string[regexp, capture = 0]
string[substring]

string[index]

When a non-negative integer argument #index is given, the slice is the 1-character substring found in self at character offset #index:

'bar'[0]      # => "b"
'bar'[2]      # => "r"
'bar'[20]     # => nil
'тест'[2]     # => "с"
'こんにちは'[4] # => "は"

When a negative integer #index is given, the slice begins at the offset given by counting backward from the end of self:

'bar'[-3]      # => "b"
'bar'[-1]      # => "r"
'bar'[-20]     # => nil

string[start, length]

When non-negative integer arguments start and #length are given, the slice begins at character offset start, if it exists, and continues for #length characters, if available:

'foo'[0, 2]      # => "fo"
'тест'[1, 2]     # => "ес"
'こんにちは'[2, 2] # => "にち"
# Zero length.
'foo'[2, 0]      # => ""
# Length not entirely available.
'foo'[1, 200]    # => "oo"
# Start out of range.
'foo'[4, 2]      # => nil

Special case: if start equals the length of self, the slice is a new empty string:

'foo'[3, 2]    # => ""
'foo'[3, 200]  # => ""

When a negative start and non-negative #length are given, the slice begins by counting backward from the end of self, and continues for #length characters, if available:

'foo'[-2, 2]     # => "oo"
'foo'[-2, 200]   # => "oo"
# Start out of range.
'foo'[-4, 2]     # => nil

When a negative #length is given, there is no slice:

'foo'[1, -1]   # => nil
'foo'[-2, -1]  # => nil

string[range]

When a ::Range argument range is given, it creates a substring of string using the indices in range. The slice is then determined as above:

'foo'[0..1]     # => "fo"
'foo'[0, 2]     # => "fo"

'foo'[2...2]    # => ""
'foo'[2, 0]     # => ""

'foo'[1..200]   # => "oo"
'foo'[1, 200]   # => "oo"

'foo'[4..5]     # => nil
'foo'[4, 2]     # => nil

'foo'[-4..-3]   # => nil
'foo'[-4, 2]    # => nil

'foo'[3..4]     # => ""
'foo'[3, 2]     # => ""

'foo'[-2..-1]   # => "oo"
'foo'[-2, 2]    # => "oo"

'foo'[-2..197]  # => "oo"
'foo'[-2, 200]  # => "oo"

string[regexp, capture = 0]

When the ::Regexp argument regexp is given, and the capture argument is 0, the slice is the first matching substring found in self:

'foo'[/o/]                # => "o"
'foo'[/x/]                # => nil
s = 'hello there'
s[/[aeiou](.)\1/]        # => "ell"
s[/[aeiou](.)\1/, 0]     # => "ell"

If the argument capture is provided and not 0, it should be either a capture group index (integer) or a capture group name (String or ::Symbol); the slice is the specified capture (see Regexp@Groups and Captures):

s = 'hello there'
s[/[aeiou](.)\1/, 1] # => "l"
s[/(?<vowel>[aeiou])(?<non_vowel>[^aeiou])/, "non_vowel"] # => "l"
s[/(?<vowel>[aeiou])(?<non_vowel>[^aeiou])/, :vowel]      # => "e"

If an invalid capture group index is given, there is no slice. If an invalid capture group name is given, ::IndexError is raised.

string[substring]

When the single String argument substring is given, it returns the substring from self if found, otherwise nil:

'foo'['oo'] # => "oo"
'foo'['xx'] # => nil

What’s Here

First, what’s elsewhere. ::Class String:

Inherits from the {Object class}.
Includes the {Comparable module}.

Here, class String provides methods that are useful for:

{String@Creating+a+String Creating a }.
{String@Freezing-2FUnfreezing Freezing/Unfreezing a }.
{String@Querying Querying a }.
Comparing s.
{String@Modifying Modifying a }.
{String@Converting+to+New+String Converting to a new }.
Converting to a non-.
{String@Iterating Iterating over a }.

Creating a String

.new: Returns a new string.
.try_convert: Returns a new string created from a given object.

Freezing/Unfreezing

#+@: Returns a string that is not frozen: self if not frozen; self.dup otherwise.
#-@ (aliased as #dedup): Returns a string that is frozen: self if already frozen; self.freeze otherwise.
#freeze: Freezes self if not already frozen; returns self.

Querying

Counts

#length (aliased as #size): Returns the count of characters (not bytes).
#empty?: Returns true if self.length is zero; false otherwise.
#bytesize: Returns the count of bytes.
#count: Returns the count of substrings matching given strings.

Substrings

#=~: Returns the index of the first substring that matches a given Regexp or other object; returns nil if no match is found.
#byteindex: Returns the byte index of the first occurrence of a given substring.
#byterindex: Returns the byte index of the last occurrence of a given substring.
#index: Returns the index of the first occurrence of a given substring; returns nil if none found.
#rindex: Returns the index of the last occurrence of a given substring; returns nil if none found.
#include?: Returns true if the string contains a given substring; false otherwise.
#match: Returns a ::MatchData object if the string matches a given Regexp; nil otherwise.
#match?: Returns true if the string matches a given Regexp; false otherwise.
#start_with?: Returns true if the string begins with any of the given substrings.
#end_with?: Returns true if the string ends with any of the given substrings.

Encodings

#encoding: Returns the ::Encoding object that represents the encoding of the string.
#unicode_normalized?: Returns true if the string is in Unicode normalized form; false otherwise.
#valid_encoding?: Returns true if the string contains only characters that are valid for its encoding.
#ascii_only?: Returns true if the string has only ASCII characters; false otherwise.

Other

#sum: Returns a basic checksum for the string: the sum of each byte.
#hash: Returns the integer hash code.

Comparing

#== (aliased as #===): Returns true if a given other string has the same content as self.
#eql?: Returns true if the content is the same as the given other string.
#<=>: Returns -1, 0, or 1 as a given other string is smaller than, equal to, or larger than self.
#casecmp: Ignoring case, returns -1, 0, or 1 as a given other string is smaller than, equal to, or larger than self.
#casecmp?: Returns true if the string is equal to a given string after Unicode case folding; false otherwise.

Modifying

Each of these methods modifies self.

Insertion

#insert: Returns self with a given string inserted at a specified offset.
#<<: Returns self concatenated with a given string or integer.
#append_as_bytes: Returns self concatenated with strings without performing any encoding validation or conversion.

Substitution

#bytesplice: Replaces bytes of self with bytes from a given string; returns self.
#sub!: Replaces the first substring that matches a given pattern with a given replacement string; returns self if any changes, nil otherwise.
#gsub!: Replaces each substring that matches a given pattern with a given replacement string; returns self if any changes, nil otherwise.
#succ! (aliased as #next!): Returns self modified to become its own successor.
#initialize_copy (aliased as #replace): Returns self with its entire content replaced by a given string.
#reverse!: Returns self with its characters in reverse order.
#setbyte: Sets the byte at a given integer offset to a given value; returns the argument.
#tr!: Replaces specified characters in self with specified replacement characters; returns self if any changes, nil otherwise.
#tr_s!: Replaces specified characters in self with specified replacement characters, removing duplicates from the substrings that were modified; returns self if any changes, nil otherwise.

Casing

#capitalize!: Upcases the initial character and downcases all others; returns self if any changes, nil otherwise.
#downcase!: Downcases all characters; returns self if any changes, nil otherwise.
#upcase!: Upcases all characters; returns self if any changes, nil otherwise.
#swapcase!: Upcases each downcase character and downcases each upcase character; returns self if any changes, nil otherwise.

Encoding

#encode!: Returns self with all characters transcoded from one encoding to another.
#unicode_normalize!: Unicode-normalizes self; returns self.
#scrub!: Replaces each invalid byte with a given character; returns self.
#force_encoding: Changes the encoding to a given encoding; returns self.

Deletion

#clear: Removes all content, so that self is empty; returns self.
#slice!, #[]=: Removes a substring determined by a given index, start/length, range, regexp, or substring.
#squeeze!: Removes contiguous duplicate characters; returns self.
#delete!: Removes characters as determined by the intersection of substring arguments.
#lstrip!: Removes leading whitespace; returns self if any changes, nil otherwise.
#rstrip!: Removes trailing whitespace; returns self if any changes, nil otherwise.
#strip!: Removes leading and trailing whitespace; returns self if any changes, nil otherwise.
#chomp!: Removes the trailing record separator, if found; returns self if any changes, nil otherwise.
#chop!: Removes trailing newline characters if found; otherwise removes the last character; returns self if any changes, nil otherwise.

Converting to New String

Each of these methods returns a new String based on self, often just a modified copy of self.

Extension

#*: Returns the concatenation of multiple copies of self.
#+: Returns the concatenation of self and a given other string.
#center: Returns a copy of self centered between pad substrings.
#concat: Returns the concatenation of self with given other strings.
#prepend: Returns the concatenation of a given other string with self.
#ljust: Returns a copy of self of a given length, right-padded with a given other string.
#rjust: Returns a copy of self of a given length, left-padded with a given other string.

Encoding

#b: Returns a copy of self with ASCII-8BIT encoding.
#scrub: Returns a copy of self with each invalid byte replaced with a given character.
#unicode_normalize: Returns a copy of self with each character Unicode-normalized.
#encode: Returns a copy of self with all characters transcoded from one encoding to another.

Substitution

#dump: Returns a copy of self with all non-printing characters replaced by xHH notation and all special characters escaped.
#undump: Returns a copy of self with all \xNN notations replaced by \uNNNN notations and all escaped characters unescaped.
#sub: Returns a copy of self with the first substring matching a given pattern replaced with a given replacement string.
#gsub: Returns a copy of self with each substring that matches a given pattern replaced with a given replacement string.
#succ (aliased as #next): Returns the string that is the successor to self.
#reverse: Returns a copy of self with its characters in reverse order.
#tr: Returns a copy of self with specified characters replaced with specified replacement characters.
#tr_s: Returns a copy of self with specified characters replaced with specified replacement characters, removing duplicates from the substrings that were modified.
#%: Returns the string resulting from formatting a given object into self.

Casing

#capitalize: Returns a copy of self with the first character upcased and all other characters downcased.
#downcase: Returns a copy of self with all characters downcased.
#upcase: Returns a copy of self with all characters upcased.
#swapcase: Returns a copy of self with all upcase characters downcased and all downcase characters upcased.

Deletion

#delete: Returns a copy of self with characters removed.
#delete_prefix: Returns a copy of self with a given prefix removed.
#delete_suffix: Returns a copy of self with a given suffix removed.
#lstrip: Returns a copy of self with leading whitespace removed.
#rstrip: Returns a copy of self with trailing whitespace removed.
#strip: Returns a copy of self with leading and trailing whitespace removed.
#chomp: Returns a copy of self with a trailing record separator removed, if found.
#chop: Returns a copy of self with trailing newline characters or the last character removed.
#squeeze: Returns a copy of self with contiguous duplicate characters removed.
#[] (aliased as #slice): Returns a substring determined by a given index, start/length, range, regexp, or string.
#byteslice: Returns a substring determined by a given index, start/length, or range.
#chr: Returns the first character.

Duplication

#to_s (aliased as #to_str): If self is a subclass of String, returns self copied into a String; otherwise, returns self.

Converting to Non-String

Each of these methods converts the contents of self to a non-String.

Characters, Bytes, and Clusters

#bytes: Returns an array of the bytes in self.
#chars: Returns an array of the characters in self.
#codepoints: Returns an array of the integer ordinals in self.
#getbyte: Returns the integer byte at the given index in self.
#grapheme_clusters: Returns an array of the grapheme clusters in self.

Splitting

#lines: Returns an array of the lines in self, as determined by a given record separator.
#partition: Returns a 3-element array determined by the first substring that matches a given substring or regexp.
#rpartition: Returns a 3-element array determined by the last substring that matches a given substring or regexp.
#split: Returns an array of substrings determined by a given delimiter – regexp or string – or, if a block is given, passes those substrings to the block.

Matching

#scan: Returns an array of substrings matching a given regexp or string, or, if a block is given, passes each matching substring to the block.
#unpack: Returns an array of substrings extracted from self according to a given format.
#unpack1: Returns the first substring extracted from self according to a given format.

Numerics

#hex: Returns the integer value of the leading characters, interpreted as hexadecimal digits.
#oct: Returns the integer value of the leading characters, interpreted as octal digits.
#ord: Returns the integer ordinal of the first character in self.
#to_i: Returns the integer value of leading characters, interpreted as an integer.
#to_f: Returns the floating-point value of leading characters, interpreted as a floating-point number.

Strings and Symbols

#inspect: Returns a copy of self, enclosed in double quotes, with special characters escaped.
#intern (aliased as #to_sym): Returns the symbol corresponding to self.

Iterating

#each_byte: Calls the given block with each successive byte in self.
#each_char: Calls the given block with each successive character in self.
#each_codepoint: Calls the given block with each successive integer codepoint in self.
#each_grapheme_cluster: Calls the given block with each successive grapheme cluster in self.
#each_line: Calls the given block with each successive line in self, as determined by a given record separator.
#upto: Calls the given block with each string value returned by successive calls to #succ.

Class Method Summary

.try_convert(object) ⇒ Object, ...

Attempts to convert the given object to a string.
.new(*args) constructor Internal use only

Instance Attribute Summary

#ascii_only? ⇒ Boolean readonly

Returns whether self contains only ASCII characters:
#empty? ⇒ Boolean readonly

Returns true if the length of self is zero, false otherwise:
#valid_encoding? ⇒ Boolean readonly

Returns true if self is encoded correctly, false otherwise:

Instance Method Summary

#%(object) ⇒ String

Returns the result of formatting object into the format specifications contained in self (see Format Specifications):
#*(n) ⇒ String

Returns a new string containing n copies of self:
#+(other_string) ⇒ String

Returns a new string containing other_string concatenated to self:
#+ ⇒ String, self

Returns self if self is not frozen and can be mutated without warning issuance.
#- ⇒ String (also: #dedup)

Returns a frozen string equal to self.
#<<(object) ⇒ self

Appends a string representation of object to self; returns self.
#<=>(other_string) ⇒ 1, ...

Compares self and other_string, returning:
#==(object) ⇒ Boolean (also: #===)

Returns whether object is equal to self.
#===(object) ⇒ Boolean

Alias for #==.
#=~(object) ⇒ Integer^?

When object is a ::Regexp, returns the index of the first substring in self matched by object, or nil if no match is found; updates Regexp-related global variables:
#[](index) ⇒ String^? (also: #slice)

Returns the substring of self specified by the arguments.
#[]=(index, new_string)

Replaces all, some, or none of the contents of self; returns new_string.
#append_as_bytes(*objects) ⇒ self

Concatenates each object in objects into self; returns self; performs no encoding validation or conversion:
#b ⇒ String

Returns a copy of self that has ASCII-8BIT encoding; the underlying bytes are not modified:
#byteindex(object, offset = 0) ⇒ Integer^?

Returns the 0-based integer index of a substring of self specified by object (a string or ::Regexp) and offset, or nil if there is no such substring; the returned index is the count of bytes (not characters).
#byterindex(object, offset = self.bytesize) ⇒ Integer^?

Returns the 0-based integer index of a substring of self that is the last match for the given object (a string or ::Regexp) and offset, or nil if there is no such substring; the returned index is the count of bytes (not characters).
#bytes ⇒ array_of_bytes

Returns an array of the bytes in self:
#bytesize ⇒ Integer

Returns the count of bytes in self.
#byteslice(offset, length = 1) ⇒ String^?

Returns a substring of self, or nil if the substring cannot be constructed.
#bytesplice(offset, length, str) ⇒ self

Replaces target bytes in self with source bytes from the given string str; returns self.
#capitalize(mapping = :ascii) ⇒ String

Returns a string containing the characters in self, each with possibly changed case:
#capitalize!(mapping = :ascii) ⇒ self^?

Like #capitalize, except that:
#casecmp(other_string) ⇒ 1, ...

Compares self.downcase and other_string.downcase; returns:
#casecmp?(other_string) ⇒ true, ...

Returns true if self and other_string are equal after Unicode case folding, otherwise false:
#center(size, pad_string = ' ') ⇒ String

Returns a centered copy of self.
#chars ⇒ array_of_characters

Returns an array of the characters in self:
#chomp(line_sep = $/) ⇒ String

Returns a new string copied from self, with trailing characters possibly removed:
#chomp!(line_sep = $/) ⇒ self^?

Like #chomp, but modifies self in place; returns nil if no modification made, self otherwise.
#chop ⇒ String

Returns a new string copied from self, with trailing characters possibly removed.
#chop! ⇒ self^?

Like #chop, but modifies self in place; returns nil if self is empty, self otherwise.
#chr ⇒ String

Returns a string containing the first character of self:
#clear ⇒ self

Removes the contents of self:
#codepoints ⇒ array_of_integers

Returns an array of the codepoints in self; each codepoint is the integer value for a character:
#concat(*objects) ⇒ String

Concatenates each object in objects to self and returns self:
#count(*selectors) ⇒ Integer

Returns the total number of characters in self that are specified by the given selectors (see Multiple Character Selectors):
#crypt(salt_str) ⇒ String

Returns the string generated by calling crypt(3) standard library function with str and salt_str, in this order, as its arguments.
#dedup ⇒ String

Alias for #-@.
#delete(*selectors) ⇒ String

Returns a copy of self with characters specified by selectors removed (see Multiple Character Selectors):
#delete!(*selectors) ⇒ self^?

Like #delete, but modifies self in place.
#delete_prefix(prefix) ⇒ String

Returns a copy of self with leading substring prefix removed:
#delete_prefix!(prefix) ⇒ self^?

Like #delete_prefix, except that self is modified in place.
#delete_suffix(suffix) ⇒ String

Returns a copy of self with trailing substring suffix removed:
#delete_suffix!(suffix) ⇒ self^?

Like #delete_suffix, except that self is modified in place.
#downcase(mapping) ⇒ String

Returns a string containing the downcased characters in self:
#downcase!(mapping) ⇒ self^?

Downcases the characters in self; returns self if any changes were made, nil otherwise:
#dump ⇒ String

Returns a printable version of self, enclosed in double-quotes, with special characters escaped, and with non-printing characters replaced by hexadecimal notation:
#each_byte {|byte| ... } ⇒ self

Calls the given block with each successive byte from self; returns self:
#each_char {|c| ... } ⇒ self

Calls the given block with each successive character from self; returns self:
#each_codepoint {|integer| ... } ⇒ self

Calls the given block with each successive codepoint from self; each codepoint is the integer value for a character; returns self:
#each_grapheme_cluster {|gc| ... } ⇒ self
#each_line(line_sep = $/, chomp: false) {|substring| ... } ⇒ self

With a block given, forms the substrings (???lines???) that are the result of splitting self at each occurrence of the given line separator line_sep; passes each line to the block; returns self:
#encode(dst_encoding = Encoding.default_internal, **enc_opts) ⇒ String

Returns a copy of self transcoded as determined by dst_encoding.
#encode!(dst_encoding = Encoding.default_internal, **enc_opts) ⇒ self

Like #encode, but applies encoding changes to self; returns self.
#encoding ⇒ Encoding

Alias for Regexp#encoding.
#end_with?(*strings) ⇒ Boolean

Returns whether self ends with any of the given strings.
#eql?(object) ⇒ Boolean

Returns true if object has the same length and content; as self; false otherwise:
#force_encoding(encoding) ⇒ self

Changes the encoding of self to encoding, which may be a string encoding name or an ::Encoding object; returns self:
#getbyte(index) ⇒ Integer^?

Returns the byte at zero-based #index as an integer, or nil if #index is out of range:
#grapheme_clusters ⇒ array_of_grapheme_clusters

Returns an array of the grapheme clusters in self (see Unicode Grapheme Cluster Boundaries):
#gsub(pattern, replacement) ⇒ String

Returns a copy of self with all occurrences of the given pattern replaced.
#gsub!(pattern, replacement) ⇒ self^?

Performs the specified substring replacement(s) on self; returns self if any replacement occurred, nil otherwise.
#hash ⇒ Integer

Returns the integer hash value for self.
#hex ⇒ Integer

Interprets the leading substring of self as a string of hexadecimal digits (with an optional sign and an optional 0x) and returns the corresponding number; returns zero if there is no such leading substring:
#include?(other_string) ⇒ Boolean

Returns true if self contains other_string, false otherwise:
#index(substring, offset = 0) ⇒ Integer^?

Returns the integer index of the first match for the given argument, or nil if none found; the search of self is forward, and begins at position offset (in characters).
#new(string = ''.encode(Encoding::ASCII_8BIT), **options) ⇒ String constructor

Returns a new String object containing the given string.
#initialize_copy(other_string) ⇒ self

Alias for #replace.
#insert(index, other_string) ⇒ self

Inserts the given other_string into self; returns self.
#inspect ⇒ String

Returns a printable version of self, enclosed in double-quotes, and with special characters escaped:
#intern ⇒ Symbol (also: #to_sym)

Returns the ::Symbol corresponding to str, creating the symbol if it did not previously exist.
#length ⇒ Integer (also: #size)

Returns the count of characters (not bytes) in self:
#lines(Line_sep = $/, chomp: false) ⇒ String

Forms substrings (“lines”) of self according to the given arguments (see #each_line for details); returns the lines in an array.
#ljust(size, pad_string = ' ') ⇒ String

Returns a left-justified copy of self.
#lstrip ⇒ String

Returns a copy of self with leading whitespace removed; see Whitespace in Strings:
#lstrip! ⇒ self^?

Like #lstrip, except that any modifications are made in self; returns self if any modification are made, nil otherwise.
#match(pattern, offset = 0) ⇒ MatchData^?

Returns a ::MatchData object (or nil) based on self and the given pattern.
#match?(pattern, offset = 0) ⇒ Boolean

Returns true or false based on whether a match is found for self and pattern.
#next ⇒ String (also: #succ)

Returns the successor to self.
#next! ⇒ self (also: #succ!)

Equivalent to #succ, but modifies self in place; returns self.
#oct ⇒ Integer

Interprets the leading substring of self as a string of octal digits (with an optional sign) and returns the corresponding number; returns zero if there is no such leading substring:
#ord ⇒ Integer

Returns the integer ordinal of the first character of self:
#partition(string_or_regexp) ⇒ Array, ...

Returns a 3-element array of substrings of self.
#prepend(*other_strings) ⇒ String

Prepends each string in other_strings to self and returns self:
#replace(other_string) ⇒ self (also: #initialize_copy)

Replaces the contents of self with the contents of other_string:
#reverse ⇒ String

Returns a new string with the characters from self in reverse order.
#reverse! ⇒ self

Returns self with its characters reversed:
#rindex(substring, offset = self.length) ⇒ Integer^?

Returns the ::Integer index of the last occurrence of the given substring, or nil if none found:
#rjust(size, pad_string = ' ') ⇒ String

Returns a right-justified copy of self.
#rpartition(sep) ⇒ Array, ...

Returns a 3-element array of substrings of self.
#rstrip ⇒ String

Returns a copy of the receiver with trailing whitespace removed; see Whitespace in Strings:
#rstrip! ⇒ self^?

Like #rstrip, except that any modifications are made in self; returns self if any modification are made, nil otherwise.
#scan(string_or_regexp) ⇒ Array

Matches a pattern against self; the pattern is:
#scrub(replacement_string = default_replacement) ⇒ String

Returns a copy of self with each invalid byte sequence replaced by the given replacement_string.
#scrub! ⇒ self

Like #scrub, except that any replacements are made in self.
#setbyte(index, integer) ⇒ Integer

Sets the byte at zero-based #index to integer; returns integer:
#size ⇒ Integer

Alias for #length.
#[](index) ⇒ String^?

Alias for #[].
#slice!(index) ⇒ String^?

Removes and returns the substring of self specified by the arguments.
#split(field_sep = $;, limit = 0) ⇒ Array

Returns an array of substrings of self that are the result of splitting self at each occurrence of the given field separator field_sep.
#squeeze(*selectors) ⇒ String

Returns a copy of self with characters specified by selectors “squeezed” (see Multiple Character Selectors):
#squeeze!(*selectors) ⇒ self^?

Like #squeeze, but modifies self in place.
#start_with?(*string_or_regexp) ⇒ Boolean

Returns whether self starts with any of the given string_or_regexp.
#strip ⇒ String

Returns a copy of the receiver with leading and trailing whitespace removed; see Whitespace in Strings:
#strip! ⇒ self^?

Like #strip, except that any modifications are made in self; returns self if any modification are made, nil otherwise.
#sub(pattern, replacement) ⇒ String

Returns a copy of self with only the first occurrence (not all occurrences) of the given pattern replaced.
#sub!(pattern, replacement) ⇒ self^?

Replaces the first occurrence (not all occurrences) of the given pattern on self; returns self if a replacement occurred, nil otherwise.
#succ ⇒ String

Alias for #next.
#succ! ⇒ self

Alias for #next!.
#sum(n = 16) ⇒ Integer

Returns a basic n-bit checksum of the characters in self; the checksum is the sum of the binary value of each byte in self, modulo 2**n - 1:
#swapcase(mapping) ⇒ String

Returns a string containing the characters in self, with cases reversed; each uppercase character is downcased; each lowercase character is upcased:
#swapcase!(mapping) ⇒ self^?

Upcases each lowercase character in self; downcases uppercase character; returns self if any changes were made, nil otherwise:
#to_c ⇒ Complex

Returns self interpreted as a ::Complex object; leading whitespace and trailing garbage are ignored:
#to_f ⇒ Float

Returns the result of interpreting leading characters in self as a ::Float:
#to_i(base = 10) ⇒ Integer

Returns the result of interpreting leading characters in self as an integer in the given base (which must be in (0, 2..36)):
#to_r ⇒ Rational

Returns the result of interpreting leading characters in str as a rational.
#to_s ⇒ self, String (also: #to_str)

Returns self if self is a String, or self converted to a String if self is a subclass of String.
#to_str ⇒ self, String

Alias for #to_s.
#to_sym ⇒ Symbol

Alias for #intern.
#tr(selector, replacements) ⇒ String

Returns a copy of self with each character specified by string selector translated to the corresponding character in string replacements.
#tr!(selector, replacements) ⇒ self^?

Like #tr, but modifies self in place.
#tr_s(selector, replacements) ⇒ String

Like #tr, but also squeezes the modified portions of the translated string; returns a new string (translated and squeezed).
#tr_s!(selector, replacements) ⇒ self^?

Like #tr_s, but modifies self in place.
#undump ⇒ String

Returns an unescaped version of self:
#unicode_normalize(form = :nfc) ⇒ String

Returns a copy of self with Unicode normalization applied.
#unicode_normalize!(form = :nfc) ⇒ self

Like #unicode_normalize, except that the normalization is performed on self.
#unicode_normalized?(form = :nfc) ⇒ Boolean

Returns true if self is in the given form of Unicode normalization, false otherwise.
#unpack(template, offset: 0, &block) ⇒ Array

Extracts data from self.
#unpack1(template, offset: 0) ⇒ Object

Like #unpack, but unpacks and returns only the first extracted object.
#upcase(mapping) ⇒ String

Returns a string containing the upcased characters in self:
#upcase!(mapping) ⇒ self^?

Upcases the characters in self; returns self if any changes were made, nil otherwise:
#upto(other_string, exclusive = false) {|string| ... } ⇒ self

With a block given, calls the block with each String value returned by successive calls to String#succ; the first value is self, the next is self.succ, and so on; the sequence terminates when value other_string is reached; returns self:
#dup Internal use only
#freeze Internal use only

`::Comparable` - Included

#<	Compares two objects based on the receiver’s #<=> method, returning true if it returns a value less than 0.
#<=	Compares two objects based on the receiver’s #<=> method, returning true if it returns a value less than or equal to 0.
#==	Compares two objects based on the receiver’s #<=> method, returning true if it returns 0.
#>	Compares two objects based on the receiver’s #<=> method, returning true if it returns a value greater than 0.
#>=	Compares two objects based on the receiver’s #<=> method, returning true if it returns a value greater than or equal to 0.
#between?	Returns `false` if obj #<=> min is less than zero or if obj #<=> max is greater than zero, `true` otherwise.
#clamp	In `(min, max)` form, returns min if obj #<=> min is less than zero, max if obj #<=> max is greater than zero, and obj otherwise.

Constructor Details

.new(*args)

This method is for internal use only.

[ GitHub ]

# File 'string.c', line 2101


static VALUE
rb_str_s_new(int argc, VALUE *argv, VALUE klass)
{
    if (klass != rb_cString) {
        return rb_class_new_instance_pass_kw(argc, argv, klass);
    }

    static ID keyword_ids[2];
    VALUE orig, opt, encoding = Qnil, capacity = Qnil;
    VALUE kwargs[2];
    rb_encoding *enc = NULL;

    int n = rb_scan_args(argc, argv, "01:", &orig, &opt);
    if (NIL_P(opt)) {
        return rb_class_new_instance_pass_kw(argc, argv, klass);
    }

    keyword_ids[0] = rb_id_encoding();
    CONST_ID(keyword_ids[1], "capacity");
    rb_get_kwargs(opt, keyword_ids, 0, 2, kwargs);
    encoding = kwargs[0];
    capacity = kwargs[1];

    if (n == 1) {
        orig = StringValue(orig);
    }
    else {
        orig = Qnil;
    }

    if (UNDEF_P(encoding)) {
        if (!NIL_P(orig)) {
            encoding = rb_obj_encoding(orig);
        }
    }

    if (!UNDEF_P(encoding)) {
        enc = rb_to_encoding(encoding);
    }

    // If capacity is nil, we're basically just duping `orig`.
    if (UNDEF_P(capacity)) {
        if (NIL_P(orig)) {
            VALUE empty_str = str_new(klass, "", 0);
            if (enc) {
                rb_enc_associate(empty_str, enc);
            }
            return empty_str;
        }
        VALUE copy = str_duplicate(klass, orig);
        rb_enc_associate(copy, enc);
        ENC_CODERANGE_CLEAR(copy);
        return copy;
    }

    long capa = 0;
    capa = NUM2LONG(capacity);
    if (capa < 0) {
        capa = 0;
    }

    if (!NIL_P(orig)) {
        long orig_capa = rb_str_capacity(orig);
        if (orig_capa > capa) {
            capa = orig_capa;
        }
    }

    VALUE str = str_enc_new(klass, NULL, capa, enc);
    STR_SET_LEN(str, 0);
    TERM_FILL(RSTRING_PTR(str), enc ? rb_enc_mbmaxlen(enc) : 1);

    if (!NIL_P(orig)) {
        rb_str_buf_append(str, orig);
    }

    return str;
}

#new(string = ''.encode(Encoding::ASCII_8BIT), **options) ⇒ `String`

Returns a new String object containing the given string.

The options are optional keyword options (see below).

With no argument given and keyword #encoding also not given, returns an empty string with the ::Encoding ASCII-8BIT:

s = String.new # => ""
s.encoding     # => #<Encoding:ASCII-8BIT>

With argument string given and keyword option #encoding not given, returns a new string with the same encoding as string:

s0 = 'foo'.encode(Encoding::UTF_16)
s1 = String.new(s0)
s1.encoding # => #<Encoding:UTF-16 (dummy)>

(Unlike String.new, a string literal like '' or a here document literal always has script encoding.)

With keyword option #encoding given, returns a string with the specified encoding; the #encoding may be an ::Encoding object, an encoding name, or an encoding name alias:

String.new(encoding: Encoding::US_ASCII).encoding        # => #<Encoding:US-ASCII>
String.new('', encoding: Encoding::US_ASCII).encoding    # => #<Encoding:US-ASCII>
String.new('foo', encoding: Encoding::US_ASCII).encoding # => #<Encoding:US-ASCII>
String.new('foo', encoding: 'US-ASCII').encoding         # => #<Encoding:US-ASCII>
String.new('foo', encoding: 'ASCII').encoding            # => #<Encoding:US-ASCII>

The given encoding need not be valid for the string’s content, and its validity is not checked:

s = String.new('こんにちは', encoding: 'ascii')
s.valid_encoding? # => false

But the given #encoding itself is checked:

String.new('foo', encoding: 'bar') # Raises ArgumentError.

With keyword option capacity given, the given value is advisory only, and may or may not set the size of the internal buffer, which may in turn affect performance:

String.new('foo', capacity: 1)    # Buffer size is at least 4 (includes terminal null byte).
String.new('foo', capacity: 4096) # Buffer size is at least 4;
                                  # may be equal to, greater than, or less than 4096.

[ GitHub ]

# File 'string.c', line 2023


static VALUE
rb_str_init(int argc, VALUE *argv, VALUE str)
{
    static ID keyword_ids[2];
    VALUE orig, opt, venc, vcapa;
    VALUE kwargs[2];
    rb_encoding *enc = 0;
    int n;

    if (!keyword_ids[0]) {
        keyword_ids[0] = rb_id_encoding();
        CONST_ID(keyword_ids[1], "capacity");
    }

    n = rb_scan_args(argc, argv, "01:", &orig, &opt);
    if (!NIL_P(opt)) {
        rb_get_kwargs(opt, keyword_ids, 0, 2, kwargs);
        venc = kwargs[0];
        vcapa = kwargs[1];
        if (!UNDEF_P(venc) && !NIL_P(venc)) {
            enc = rb_to_encoding(venc);
        }
        if (!UNDEF_P(vcapa) && !NIL_P(vcapa)) {
            long capa = NUM2LONG(vcapa);
            long len = 0;
            int termlen = enc ? rb_enc_mbminlen(enc) : 1;

            if (capa < STR_BUF_MIN_SIZE) {
                capa = STR_BUF_MIN_SIZE;
            }
            if (n == 1) {
                StringValue(orig);
                len = RSTRING_LEN(orig);
                if (capa < len) {
                    capa = len;
                }
                if (orig == str) n = 0;
            }
            str_modifiable(str);
            if (STR_EMBED_P(str) || FL_TEST(str, STR_SHARED|STR_NOFREE)) {
                /* make noembed always */
                const size_t size = (size_t)capa + termlen;
                const char *const old_ptr = RSTRING_PTR(str);
                const size_t osize = RSTRING_LEN(str) + TERM_LEN(str);
                char *new_ptr = ALLOC_N(char, size);
                if (STR_EMBED_P(str)) RUBY_ASSERT((long)osize <= str_embed_capa(str));
                memcpy(new_ptr, old_ptr, osize < size ? osize : size);
                FL_UNSET_RAW(str, STR_SHARED|STR_NOFREE);
                RSTRING(str)->as.heap.ptr = new_ptr;
            }
            else if (STR_HEAP_SIZE(str) != (size_t)capa + termlen) {
                SIZED_REALLOC_N(RSTRING(str)->as.heap.ptr, char,
                        (size_t)capa + termlen, STR_HEAP_SIZE(str));
            }
            STR_SET_LEN(str, len);
            TERM_FILL(&RSTRING(str)->as.heap.ptr[len], termlen);
            if (n == 1) {
                memcpy(RSTRING(str)->as.heap.ptr, RSTRING_PTR(orig), len);
                rb_enc_cr_str_exact_copy(str, orig);
            }
            FL_SET(str, STR_NOEMBED);
            RSTRING(str)->as.heap.aux.capa = capa;
        }
        else if (n == 1) {
            rb_str_replace(str, orig);
        }
        if (enc) {
            rb_enc_associate(str, enc);
            ENC_CODERANGE_CLEAR(str);
        }
    }
    else if (n == 1) {
        rb_str_replace(str, orig);
    }
    return str;
}

Class Method Details

.try_convert(object) ⇒ Object, ...

Attempts to convert the given object to a string.

If object is already a string, returns object, unmodified.

Otherwise if object responds to :to_str, calls object.to_str and returns the result.

Returns nil if object does not respond to :to_str.

Raises an exception unless object.to_str returns a string.

[ GitHub ]

# File 'string.c', line 2929


static VALUE
rb_str_s_try_convert(VALUE dummy, VALUE str)
{
    return rb_check_string_type(str);
}

Instance Attribute Details

#ascii_only? ⇒ `Boolean` (readonly)

Returns whether self contains only ASCII characters:

'abc'.ascii_only?         # => true
"abc\u{6666}".ascii_only? # => false

Related: see Querying.

[ GitHub ]

# File 'string.c', line 11584


static VALUE
rb_str_is_ascii_only_p(VALUE str)
{
    int cr = rb_enc_str_coderange(str);

    return RBOOL(cr == ENC_CODERANGE_7BIT);
}

#empty? ⇒ `Boolean` (readonly)

Returns true if the length of self is zero, false otherwise:

"hello".empty? # => false
" ".empty? # => false
"".empty? # => true

[ GitHub ]

# File 'string.c', line 2427


static VALUE
rb_str_empty(VALUE str)
{
    return RBOOL(RSTRING_LEN(str) == 0);
}

#valid_encoding? ⇒ `Boolean` (readonly)

Returns true if self is encoded correctly, false otherwise:

"\xc2\xa1".force_encoding(Encoding::UTF_8).valid_encoding? # => true
"\xc2".force_encoding(Encoding::UTF_8).valid_encoding?     # => false
"\x80".force_encoding(Encoding::UTF_8).valid_encoding?     # => false

[ GitHub ]

# File 'string.c', line 11564


static VALUE
rb_str_valid_encoding_p(VALUE str)
{
    int cr = rb_enc_str_coderange(str);

    return RBOOL(cr != ENC_CODERANGE_BROKEN);
}

Instance Method Details

#%(object) ⇒ `String`

Returns the result of formatting object into the format specifications contained in self (see Format Specifications):

'%05d' % 123 # => "00123"

If self contains multiple format specifications, object must be an array or hash containing the objects to be formatted:

'%-5s: %016x' % [ 'ID', self.object_id ]                # => "ID   : 00002b054ec93168"
'foo = %{foo}' % {foo: 'bar'}                           # => "foo = bar"
'foo = %{foo}, baz = %{baz}' % {foo: 'bar', baz: 'bat'} # => "foo = bar, baz = bat"

Related: see Converting to New String.

[ GitHub ]

# File 'string.c', line 2595


static VALUE
rb_str_format_m(VALUE str, VALUE arg)
{
    VALUE tmp = rb_check_array_type(arg);

    if (!NIL_P(tmp)) {
        return rb_str_format(RARRAY_LENINT(tmp), RARRAY_CONST_PTR(tmp), str);
    }
    return rb_str_format(1, &arg, str);
}

#*(n) ⇒ `String`

Returns a new string containing n copies of self:

'Ho!' * 3 # => "Ho!Ho!Ho!"
'No!' * 0 # => ""

Related: see Converting to New String.

[ GitHub ]

# File 'string.c', line 2517


VALUE
rb_str_times(VALUE str, VALUE times)
{
    VALUE str2;
    long n, len;
    char *ptr2;
    int termlen;

    if (times == INT2FIX(1)) {
        return str_duplicate(rb_cString, str);
    }
    if (times == INT2FIX(0)) {
        str2 = str_alloc_embed(rb_cString, 0);
        rb_enc_copy(str2, str);
        return str2;
    }
    len = NUM2LONG(times);
    if (len < 0) {
        rb_raise(rb_eArgError, "negative argument");
    }
    if (RSTRING_LEN(str) == 1 && RSTRING_PTR(str)[0] == 0) {
        if (STR_EMBEDDABLE_P(len, 1)) {
            str2 = str_alloc_embed(rb_cString, len + 1);
            memset(RSTRING_PTR(str2), 0, len + 1);
        }
        else {
            str2 = str_alloc_heap(rb_cString);
            RSTRING(str2)->as.heap.aux.capa = len;
            RSTRING(str2)->as.heap.ptr = ZALLOC_N(char, (size_t)len + 1);
        }
        STR_SET_LEN(str2, len);
        rb_enc_copy(str2, str);
        return str2;
    }
    if (len && LONG_MAX/len <  RSTRING_LEN(str)) {
        rb_raise(rb_eArgError, "argument too big");
    }

    len *= RSTRING_LEN(str);
    termlen = TERM_LEN(str);
    str2 = str_enc_new(rb_cString, 0, len, STR_ENC_GET(str));
    ptr2 = RSTRING_PTR(str2);
    if (len) {
        n = RSTRING_LEN(str);
        memcpy(ptr2, RSTRING_PTR(str), n);
        while (n <= len/2) {
            memcpy(ptr2 + n, ptr2, n);
            n *= 2;
        }
        memcpy(ptr2 + n, ptr2, len-n);
    }
    STR_SET_LEN(str2, len);
    TERM_FILL(&ptr2[len], termlen);
    rb_enc_cr_str_copy_for_substr(str2, str);

    return str2;
}

#+(other_string) ⇒ `String`

Returns a new string containing other_string concatenated to self:

'Hello from ' + self.to_s # => "Hello from main"

Related: see Converting to New String.

[ GitHub ]

# File 'string.c', line 2444


VALUE
rb_str_plus(VALUE str1, VALUE str2)
{
    VALUE str3;
    rb_encoding *enc;
    char *ptr1, *ptr2, *ptr3;
    long len1, len2;
    int termlen;

    StringValue(str2);
    enc = rb_enc_check_str(str1, str2);
    RSTRING_GETMEM(str1, ptr1, len1);
    RSTRING_GETMEM(str2, ptr2, len2);
    termlen = rb_enc_mbminlen(enc);
    if (len1 > LONG_MAX - len2) {
        rb_raise(rb_eArgError, "string size too big");
    }
    str3 = str_enc_new(rb_cString, 0, len1+len2, enc);
    ptr3 = RSTRING_PTR(str3);
    memcpy(ptr3, ptr1, len1);
    memcpy(ptr3+len1, ptr2, len2);
    TERM_FILL(&ptr3[len1+len2], termlen);

    ENCODING_CODERANGE_SET(str3, rb_enc_to_index(enc),
                           ENC_CODERANGE_AND(ENC_CODERANGE(str1), ENC_CODERANGE(str2)));
    RB_GC_GUARD(str1);
    RB_GC_GUARD(str2);
    return str3;
}

#+ ⇒ `String`, `self`

Returns self if self is not frozen and can be mutated without warning issuance.

Otherwise returns self.dup, which is not frozen.

Related: see Freezing/Unfreezing.

[ GitHub ]

# File 'string.c', line 3258


static VALUE
str_uplus(VALUE str)
{
    if (OBJ_FROZEN(str) || CHILLED_STRING_P(str)) {
        return rb_str_dup(str);
    }
    else {
        return str;
    }
}

#- ⇒ `String` Also known as: #dedup

Returns a frozen string equal to self.

The returned string is self if and only if all of the following are true:

self is already frozen.
self is an instance of String (rather than of a subclass of String)
self has no instance variables set on it.

Otherwise, the returned string is a frozen copy of self.

Returning self, when possible, saves duplicating self; see {Data deduplication}.

It may also save duplicating other, already-existing, strings:

s0 = 'foo'
s1 = 'foo'
s0.object_id == s1.object_id       # => false
(-s0).object_id == (-s1).object_id # => true

Note that method #-@ is convenient for defining a constant:

FileName = -'config/database.yml'

While its alias #dedup is better suited for chaining:

'foo'.dedup.gsub!('o')

Related: see Freezing/Unfreezing.

[ GitHub ]

# File 'string.c', line 3303


static VALUE
str_uminus(VALUE str)
{
    if (!BARE_STRING_P(str) && !rb_obj_frozen_p(str)) {
        str = rb_str_dup(str);
    }
    return rb_fstring(str);
}

#<<(object) ⇒ `self`

Appends a string representation of object to self; returns self.

If object is a string, appends it to self:

s = 'foo'
s << 'bar' # => "foobar"
s          # => "foobar"

If object is an integer, its value is considered a codepoint; converts the value to a character before concatenating:

s = 'foo'
s << 33 # => "foo!"

Additionally, if the codepoint is in range 0..0xff and the encoding of self is Encoding::US_ASCII, changes the encoding to Encoding::ASCII_8BIT:

s = 'foo'.encode(Encoding::US_ASCII)
s.encoding # => #<Encoding:US-ASCII>
s << 0xff  # => "foo\xFF"
s.encoding # => #<Encoding:BINARY (ASCII-8BIT)>

Raises RangeError if that codepoint is not representable in the encoding of self:

s = 'foo'
s.encoding              # => <Encoding:UTF-8>
s << 0x00110000         # 1114112 out of char range (RangeError)
s = 'foo'.encode(Encoding::EUC_JP)
s << 0x00800080         # invalid codepoint 0x800080 in EUC-JP (RangeError)

Related: see Modifying.

[ GitHub ]

# File 'string.c', line 4003


VALUE
rb_str_concat(VALUE str1, VALUE str2)
{
    unsigned int code;
    rb_encoding *enc = STR_ENC_GET(str1);
    int encidx;

    if (RB_INTEGER_TYPE_P(str2)) {
        if (rb_num_to_uint(str2, &code) == 0) {
        }
        else if (FIXNUM_P(str2)) {
            rb_raise(rb_eRangeError, "%ld out of char range", FIX2LONG(str2));
        }
        else {
            rb_raise(rb_eRangeError, "bignum out of char range");
        }
    }
    else {
        return rb_str_append(str1, str2);
    }

    encidx = rb_ascii8bit_appendable_encoding_index(enc, code);

    if (encidx >= 0) {
        rb_str_buf_cat_byte(str1, (unsigned char)code);
    }
    else {
        long pos = RSTRING_LEN(str1);
        int cr = ENC_CODERANGE(str1);
        int len;
        char *buf;

        switch (len = rb_enc_codelen(code, enc)) {
          case ONIGERR_INVALID_CODE_POINT_VALUE:
            rb_raise(rb_eRangeError, "invalid codepoint 0x%X in %s", code, rb_enc_name(enc));
            break;
          case ONIGERR_TOO_BIG_WIDE_CHAR_VALUE:
          case 0:
            rb_raise(rb_eRangeError, "%u out of char range", code);
            break;
        }
        buf = ALLOCA_N(char, len + 1);
        rb_enc_mbcput(code, buf, enc);
        if (rb_enc_precise_mbclen(buf, buf + len + 1, enc) != len) {
            rb_raise(rb_eRangeError, "invalid codepoint 0x%X in %s", code, rb_enc_name(enc));
        }
        rb_str_resize(str1, pos+len);
        memcpy(RSTRING_PTR(str1) + pos, buf, len);
        if (cr == ENC_CODERANGE_7BIT && code > 127) {
            cr = ENC_CODERANGE_VALID;
        }
        else if (cr == ENC_CODERANGE_BROKEN) {
            cr = ENC_CODERANGE_UNKNOWN;
        }
        ENC_CODERANGE_SET(str1, cr);
    }
    return str1;
}

#<=>(other_string) ⇒ `1`, ...

Compares self and other_string, returning:

-1 if other_string is larger.
0 if the two are equal.
1 if other_string is smaller.
nil if the two are incomparable.

Examples:

'foo' <=> 'foo'  # => 0
'foo' <=> 'food' # => -1
'food' <=> 'foo' # => 1
'FOO' <=> 'foo'  # => -1
'foo' <=> 'FOO'  # => 1
'foo' <=> 1      # => nil

Related: see Comparing.

[ GitHub ]

# File 'string.c', line 4301


static VALUE
rb_str_cmp_m(VALUE str1, VALUE str2)
{
    int result;
    VALUE s = rb_check_string_type(str2);
    if (NIL_P(s)) {
        return rb_invcmp(str1, str2);
    }
    result = rb_str_cmp(str1, s);
    return INT2FIX(result);
}

#==(object) ⇒ `Boolean` Also known as: #===

Returns whether object is equal to self.

When object is a string, returns whether object has the same length and content as self:

s = 'foo'
s == 'foo'  # => true
s == 'food' # => false
s == 'FOO'  # => false

Returns false if the two strings’ encodings are not compatible:

"\u{e4 f6 fc}".encode(Encoding::ISO_8859_1) == ("\u{c4 d6 dc}") # => false

When object is not a string:

If object responds to method #to_str, object == self is called and its return value is returned.
If object does not respond to #to_str, false is returned.

Related: Comparing.

[ GitHub ]

# File 'string.c', line 4239


VALUE
rb_str_equal(VALUE str1, VALUE str2)
{
    if (str1 == str2) return Qtrue;
    if (!RB_TYPE_P(str2, T_STRING)) {
        if (!rb_respond_to(str2, idTo_str)) {
            return Qfalse;
        }
        return rb_equal(str2, str1);
    }
    return rb_str_eql_internal(str1, str2);
}

#==(object) ⇒ `Boolean` #===(object) ⇒ `Boolean`

Alias for #==.

#=~(object) ⇒ Integer^?

When object is a ::Regexp, returns the index of the first substring in self matched by object, or nil if no match is found; updates Regexp-related global variables:

'foo' =~ /f/ # => 0
$~           # => #<MatchData "f">
'foo' =~ /o/ # => 1
$~           # => #<MatchData "o">
'foo' =~ /x/ # => nil
$~           # => nil

Note that string =~ regexp is different from regexp =~ string (see Regexp#=~):

number = nil
'no. 9' =~ /(?<number>\d+)/ # => 4
number                      # => nil # Not assigned.
/(?<number>\d+)/ =~ 'no. 9' # => 4
number                      # => "9" # Assigned.

If object is not a ::Regexp, returns the value returned by object =~ self.

Related: see Querying.

[ GitHub ]

# File 'string.c', line 5070


static VALUE
rb_str_match(VALUE x, VALUE y)
{
    switch (OBJ_BUILTIN_TYPE(y)) {
      case T_STRING:
        rb_raise(rb_eTypeError, "type mismatch: String given");

      case T_REGEXP:
        return rb_reg_match(y, x);

      default:
        return rb_funcall(y, idEqTilde, 1, x);
    }
}

#[](index) ⇒ `String`^? #[](start, length) ⇒ `String`^? #[](range) ⇒ `String`^? #[](substring) ⇒ `String`^?
Also known as: #slice

Returns the substring of self specified by the arguments. See examples at String Slices.

Related: see Converting to New String.

[ GitHub ]

# File 'string.c', line 5828


static VALUE
rb_str_aref_m(int argc, VALUE *argv, VALUE str)
{
    if (argc == 2) {
        if (RB_TYPE_P(argv[0], T_REGEXP)) {
            return rb_str_subpat(str, argv[0], argv[1]);
        }
        else {
            return rb_str_substr_two_fixnums(str, argv[0], argv[1], TRUE);
        }
    }
    rb_check_arity(argc, 1, 2);
    return rb_str_aref(str, argv[0]);
}

#[]=(index, new_string) #[]=(start, length, new_string) #[]=(range, new_string) #[]=(substring, new_string)

Replaces all, some, or none of the contents of self; returns new_string. See String Slices.

A few examples:

s = 'foo'
s[2] = 'rtune'     # => "rtune"
s                  # => "fortune"
s[1, 5] = 'init'   # => "init"
s                  # => "finite"
s[3..4] = 'al'     # => "al"
s                  # => "finale"
s[/e$/] = 'ly'     # => "ly"
s                  # => "finally"
s['lly'] = 'ncial' # => "ncial"
s                  # => "financial"

Related: see Modifying.

[ GitHub ]

# File 'string.c', line 6065


static VALUE
rb_str_aset_m(int argc, VALUE *argv, VALUE str)
{
    if (argc == 3) {
        if (RB_TYPE_P(argv[0], T_REGEXP)) {
            rb_str_subpat_set(str, argv[0], argv[1], argv[2]);
        }
        else {
            rb_str_update(str, NUM2LONG(argv[0]), NUM2LONG(argv[1]), argv[2]);
        }
        return argv[2];
    }
    rb_check_arity(argc, 2, 3);
    return rb_str_aset(str, argv[0], argv[1]);
}

#append_as_bytes(*objects) ⇒ `self`

Concatenates each object in objects into self; returns self; performs no encoding validation or conversion:

s = 'foo'
s.append_as_bytes(" \xE2\x82") # => "foo \xE2\x82"
s.valid_encoding?              # => false
s.append_as_bytes("\xAC 12")
s.valid_encoding?              # => true

When a given object is an integer, the value is considered an 8-bit byte; if the integer occupies more than one byte (i.e,. is greater than 255), appends only the low-order byte (similar to #setbyte):

s = ""
s.append_as_bytes(0, 257) # => "\u0000\u0001"
s.bytesize                # => 2

Related: see Modifying.

[ GitHub ]

# File 'string.c', line 3852


VALUE
rb_str_append_as_bytes(int argc, VALUE *argv, VALUE str)
{
    long needed_capacity = 0;
    volatile VALUE t0;
    enum ruby_value_type *types = ALLOCV_N(enum ruby_value_type, t0, argc);

    for (int index = 0; index < argc; index++) {
        VALUE obj = argv[index];
        enum ruby_value_type type = types[index] = rb_type(obj);
        switch (type) {
          case T_FIXNUM:
          case T_BIGNUM:
            needed_capacity++;
            break;
          case T_STRING:
            needed_capacity += RSTRING_LEN(obj);
            break;
          default:
            rb_raise(
                rb_eTypeError,
                "wrong argument type %"PRIsVALUE" (expected String or Integer)",
                rb_obj_class(obj)
            );
            break;
        }
    }

    str_ensure_available_capa(str, needed_capacity);
    char *sptr = RSTRING_END(str);

    for (int index = 0; index < argc; index++) {
        VALUE obj = argv[index];
        enum ruby_value_type type = types[index];
        switch (type) {
          case T_FIXNUM:
          case T_BIGNUM: {
            argv[index] = obj = rb_int_and(obj, INT2FIX(0xff));
            char byte = (char)(NUM2INT(obj) & 0xFF);
            *sptr = byte;
            sptr++;
            break;
          }
          case T_STRING: {
            const char *ptr;
            long len;
            RSTRING_GETMEM(obj, ptr, len);
            memcpy(sptr, ptr, len);
            sptr += len;
            break;
          }
          default:
            rb_bug("append_as_bytes arguments should have been validated");
        }
    }

    STR_SET_LEN(str, RSTRING_LEN(str) + needed_capacity);
    TERM_FILL(sptr, TERM_LEN(str)); /* sentinel */

    int cr = ENC_CODERANGE(str);
    switch (cr) {
      case ENC_CODERANGE_7BIT: {
        for (int index = 0; index < argc; index++) {
            VALUE obj = argv[index];
            enum ruby_value_type type = types[index];
            switch (type) {
              case T_FIXNUM:
              case T_BIGNUM: {
                if (!ISASCII(NUM2INT(obj))) {
                    goto clear_cr;
                }
                break;
              }
              case T_STRING: {
                if (ENC_CODERANGE(obj) != ENC_CODERANGE_7BIT) {
                    goto clear_cr;
                }
                break;
              }
              default:
                rb_bug("append_as_bytes arguments should have been validated");
            }
        }
        break;
      }
      case ENC_CODERANGE_VALID:
        if (ENCODING_GET_INLINED(str) == ENCINDEX_ASCII_8BIT) {
            goto keep_cr;
        }
        else {
            goto clear_cr;
        }
        break;
      default:
        goto clear_cr;
        break;
    }

    RB_GC_GUARD(t0);

  clear_cr:
    // If no fast path was hit, we clear the coderange.
    // append_as_bytes is predominently meant to be used in
    // buffering situation, hence it's likely the coderange
    // will never be scanned, so it's not worth spending time
    // precomputing the coderange except for simple and common
    // situations.
    ENC_CODERANGE_CLEAR(str);
  keep_cr:
    return str;
}

#b ⇒ `String`

Returns a copy of self that has ASCII-8BIT encoding; the underlying bytes are not modified:

s = "\x99"
s.encoding   # => #<Encoding:UTF-8>
t = s.b      # => "\x99"
t.encoding   # => #<Encoding:ASCII-8BIT>

s = "\u4095" # => "䂕"
s.encoding   # => #<Encoding:UTF-8>
s.bytes      # => [228, 130, 149]
t = s.b      # => "\xE4\x82\x95"
t.encoding   # => #<Encoding:ASCII-8BIT>
t.bytes      # => [228, 130, 149]

Related: see Converting to New String.

[ GitHub ]

# File 'string.c', line 11520


static VALUE
rb_str_b(VALUE str)
{
    VALUE str2;
    if (STR_EMBED_P(str)) {
        str2 = str_alloc_embed(rb_cString, RSTRING_LEN(str) + TERM_LEN(str));
    }
    else {
        str2 = str_alloc_heap(rb_cString);
    }
    str_replace_shared_without_enc(str2, str);

    if (rb_enc_asciicompat(STR_ENC_GET(str))) {
        // BINARY strings can never be broken; they're either 7-bit ASCII or VALID.
        // If we know the receiver's code range then we know the result's code range.
        int cr = ENC_CODERANGE(str);
        switch (cr) {
          case ENC_CODERANGE_7BIT:
            ENC_CODERANGE_SET(str2, ENC_CODERANGE_7BIT);
            break;
          case ENC_CODERANGE_BROKEN:
          case ENC_CODERANGE_VALID:
            ENC_CODERANGE_SET(str2, ENC_CODERANGE_VALID);
            break;
          default:
            ENC_CODERANGE_CLEAR(str2);
            break;
        }
    }

    return str2;
}

#byteindex(object, offset = 0) ⇒ Integer^?

Returns the 0-based integer index of a substring of self specified by object (a string or ::Regexp) and offset, or nil if there is no such substring; the returned index is the count of bytes (not characters).

When object is a string, returns the index of the first found substring equal to object:

s = 'foo'          # => "foo"
s.size             # => 3 # Three 1-byte characters.
s.bytesize         # => 3 # Three bytes.
s.byteindex('f')   # => 0
s.byteindex('o')   # => 1
s.byteindex('oo')  # => 1
s.byteindex('ooo') # => nil

When object is a ::Regexp, returns the index of the first found substring matching object; updates Regexp-related global variables:

s = 'foo'
s.byteindex(/f/)   # => 0
$~                 # => #<MatchData "f">
s.byteindex(/o/)   # => 1
s.byteindex(/oo/)  # => 1
s.byteindex(/ooo/) # => nil
$~                 # => nil

Integer argument offset, if given, specifies the 0-based index of the byte where searching is to begin.

When offset is non-negative, searching begins at byte position offset:

s = 'foo'
s.byteindex('o', 1) # => 1
s.byteindex('o', 2) # => 2
s.byteindex('o', 3) # => nil

When offset is negative, counts backward from the end of self:

s = 'foo'
s.byteindex('o', -1) # => 2
s.byteindex('o', -2) # => 1
s.byteindex('o', -3) # => 1
s.byteindex('o', -4) # => nil

Raises IndexError if the byte at offset is not the first byte of a character:

s = "\uFFFF\uFFFF"       # => "\uFFFF\uFFFF"
s.size                   # => 2 # Two 3-byte characters.
s.bytesize               # => 6 # Six bytes.
s.byteindex("\uFFFF")    # => 0
s.byteindex("\uFFFF", 1) # Raises IndexError
s.byteindex("\uFFFF", 2) # Raises IndexError
s.byteindex("\uFFFF", 3) # => 3
s.byteindex("\uFFFF", 4) # Raises IndexError
s.byteindex("\uFFFF", 5) # Raises IndexError
s.byteindex("\uFFFF", 6) # => nil

Related: see Querying.

[ GitHub ]

# File 'string.c', line 4661


static VALUE
rb_str_byteindex_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE initpos;
    long pos;

    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
        long slen = RSTRING_LEN(str);
        pos = NUM2LONG(initpos);
        if (pos < 0 ? (pos += slen) < 0 : pos > slen) {
            if (RB_TYPE_P(sub, T_REGEXP)) {
                rb_backref_set(Qnil);
            }
            return Qnil;
        }
    }
    else {
        pos = 0;
    }

    str_ensure_byte_pos(str, pos);

    if (RB_TYPE_P(sub, T_REGEXP)) {
        if (rb_reg_search(sub, str, pos, 0) >= 0) {
            VALUE match = rb_backref_get();
            struct re_registers *regs = RMATCH_REGS(match);
            pos = BEG(0);
            return LONG2NUM(pos);
        }
    }
    else {
        StringValue(sub);
        pos = rb_str_byteindex(str, sub, pos);
        if (pos >= 0) return LONG2NUM(pos);
    }
    return Qnil;
}

#byterindex(object, offset = self.bytesize) ⇒ Integer^?

Returns the 0-based integer index of a substring of self that is the last match for the given object (a string or ::Regexp) and offset, or nil if there is no such substring; the returned index is the count of bytes (not characters).

When object is a string, returns the index of the last found substring equal to object:

s = 'foo'           # => "foo"
s.size              # => 3 # Three 1-byte characters.
s.bytesize          # => 3 # Three bytes.
s.byterindex('f')   # => 0
  s.byterindex('o')   # => 2
  s.byterindex('oo')  # => 1
  s.byterindex('ooo') # => nil

When object is a ::Regexp, returns the index of the last found substring matching object; updates Regexp-related global variables:

s = 'foo'
s.byterindex(/f/)   # => 0
$~                  # => #<MatchData "f">
s.byterindex(/o/)   # => 2
s.byterindex(/oo/)  # => 1
s.byterindex(/ooo/) # => nil
$~                  # => nil

The last match means starting at the possible last position, not the last of the longest matches:

s = 'foo'
s.byterindex(/o+/) # => 2
$~                 #=> #<MatchData "o">

To get the last longest match, use a negative lookbehind:

s = 'foo'
s.byterindex(/(?<!o)o+/) # => 1
$~                       # => #<MatchData "oo">

Or use method #byteindex with negative lookahead:

s = 'foo'
s.byteindex(/o+(?!.*o)/) # => 1
$~                       #=> #<MatchData "oo">

Integer argument offset, if given, specifies the 0-based index of the byte where searching is to end.

When offset is non-negative, searching ends at byte position offset:

s = 'foo'
s.byterindex('o', 0) # => nil
s.byterindex('o', 1) # => 1
s.byterindex('o', 2) # => 2
s.byterindex('o', 3) # => 2

When offset is negative, counts backward from the end of self:

s = 'foo'
s.byterindex('o', -1) # => 2
s.byterindex('o', -2) # => 1
s.byterindex('o', -3) # => nil

Raises IndexError if the byte at offset is not the first byte of a character:

s = "\uFFFF\uFFFF"        # => "\uFFFF\uFFFF"
s.size                    # => 2 # Two 3-byte characters.
s.bytesize                # => 6 # Six bytes.
s.byterindex("\uFFFF")    # => 3
s.byterindex("\uFFFF", 1) # Raises IndexError
s.byterindex("\uFFFF", 2) # Raises IndexError
s.byterindex("\uFFFF", 3) # => 3
s.byterindex("\uFFFF", 4) # Raises IndexError
s.byterindex("\uFFFF", 5) # Raises IndexError
s.byterindex("\uFFFF", 6) # => nil

Related: see Querying.

[ GitHub ]

# File 'string.c', line 5000


static VALUE
rb_str_byterindex_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE initpos;
    long pos, len = RSTRING_LEN(str);

    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
        pos = NUM2LONG(initpos);
        if (pos < 0 && (pos += len) < 0) {
            if (RB_TYPE_P(sub, T_REGEXP)) {
                rb_backref_set(Qnil);
            }
            return Qnil;
        }
        if (pos > len) pos = len;
    }
    else {
        pos = len;
    }

    str_ensure_byte_pos(str, pos);

    if (RB_TYPE_P(sub, T_REGEXP)) {
        if (rb_reg_search(sub, str, pos, 1) >= 0) {
            VALUE match = rb_backref_get();
            struct re_registers *regs = RMATCH_REGS(match);
            pos = BEG(0);
            return LONG2NUM(pos);
        }
    }
    else {
        StringValue(sub);
        pos = rb_str_byterindex(str, sub, pos);
        if (pos >= 0) return LONG2NUM(pos);
    }
    return Qnil;
}

#bytes ⇒ `array_of_bytes`

Returns an array of the bytes in self:

'hello'.bytes # => [104, 101, 108, 108, 111]
'тест'.bytes  # => [209, 130, 208, 181, 209, 129, 209, 130]
'こんにちは'.bytes
# => [227, 129, 147, 227, 130, 147, 227, 129, 171, 227, 129, 161, 227, 129, 175]

Related: see Converting to Non-String.

[ GitHub ]

# File 'string.c', line 9810


static VALUE
rb_str_bytes(VALUE str)
{
    VALUE ary = WANTARRAY("bytes", RSTRING_LEN(str));
    return rb_str_enumerate_bytes(str, ary);
}

#bytesize ⇒ Integer

Returns the count of bytes in self.

Note that the byte count may be different from the character count (returned by #size):

s = 'foo'
s.bytesize # => 3
s.size     # => 3
s = 'тест'
s.bytesize # => 8
s.size     # => 4
s = 'こんにちは'
s.bytesize # => 15
s.size     # => 5

Related: see Querying.

[ GitHub ]

# File 'string.c', line 2409


VALUE
rb_str_bytesize(VALUE str)
{
    return LONG2NUM(RSTRING_LEN(str));
}

#byteslice(offset, length = 1) ⇒ `String`^? #byteslice(range) ⇒ `String`^?

Returns a substring of self, or nil if the substring cannot be constructed.

With integer arguments offset and #length given, returns the substring beginning at the given offset and of the given #length (as available):

s = '0123456789'   # => "0123456789"
s.byteslice(2)     # => "2"
s.byteslice(200)   # => nil
s.byteslice(4, 3)  # => "456"
s.byteslice(4, 30) # => "456789"

Returns nil if #length is negative or offset falls outside of self:

s.byteslice(4, -1) # => nil
s.byteslice(40, 2) # => nil

Counts backwards from the end of self if offset is negative:

s = '0123456789'   # => "0123456789"
s.byteslice(-4)    # => "6"
s.byteslice(-4, 3) # => "678"

With Range argument range given, returns byteslice(range.begin, range.size):

s = '0123456789'    # => "0123456789"
s.byteslice(4..6)   # => "456"
s.byteslice(-6..-4) # => "456"
s.byteslice(5..2)   # => "" # range.size is zero.
s.byteslice(40..42) # => nil

The starting and ending offsets need not be on character boundaries:

s = 'こんにちは'
s.byteslice(0, 3) # => "こ"
s.byteslice(1, 3) # => "\x81\x93\xE3"

The encodings of self and the returned substring are always the same:

s.encoding                 # => #<Encoding:UTF-8>
s.byteslice(0, 3).encoding # => #<Encoding:UTF-8>
s.byteslice(1, 3).encoding # => #<Encoding:UTF-8>

But, depending on the character boundaries, the encoding of the returned substring may not be valid:

s.valid_encoding?                 # => true
s.byteslice(0, 3).valid_encoding? # => true
s.byteslice(1, 3).valid_encoding? # => false

Related: see Converting to New String.

[ GitHub ]

# File 'string.c', line 6879


static VALUE
rb_str_byteslice(int argc, VALUE *argv, VALUE str)
{
    if (argc == 2) {
        long beg = NUM2LONG(argv[0]);
        long len = NUM2LONG(argv[1]);
        return str_byte_substr(str, beg, len, TRUE);
    }
    rb_check_arity(argc, 1, 2);
    return str_byte_aref(str, argv[0]);
}

#bytesplice(offset, length, str) ⇒ `self` #bytesplice(offset, length, str, str_offset, str_length) ⇒ `self` #bytesplice(range, str) ⇒ `self` #bytesplice(range, str, str_range) ⇒ `self`

Replaces target bytes in self with source bytes from the given string str; returns self.

In the first form, arguments offset and #length determine the target bytes, and the source bytes are all of the given str:

'0123456789'.bytesplice(0, 3, 'abc')  # => "abc3456789"
'0123456789'.bytesplice(3, 3, 'abc')  # => "012abc6789"
'0123456789'.bytesplice(0, 50, 'abc') # => "abc"
'0123456789'.bytesplice(50, 3, 'abc') # Raises IndexError.

The counts of the target bytes and source source bytes may be different:

'0123456789'.bytesplice(0, 6, 'abc') # => "abc6789"      # Shorter source.
'0123456789'.bytesplice(0, 1, 'abc') # => "abc123456789" # Shorter target.

And either count may be zero (i.e., specifying an empty string):

'0123456789'.bytesplice(0, 3, '')    # => "3456789"       # Empty source.
'0123456789'.bytesplice(0, 0, 'abc') # => "abc0123456789" # Empty target.

In the second form, just as in the first, arugments offset and #length determine the target bytes; argument str contains the source bytes, and the additional arguments str_offset and str_length determine the actual source bytes:

'0123456789'.bytesplice(0, 3, 'abc', 0, 3) # => "abc3456789"
'0123456789'.bytesplice(0, 3, 'abc', 1, 1) # => "b3456789"      # Shorter source.
'0123456789'.bytesplice(0, 1, 'abc', 0, 3) # => "abc123456789"  # Shorter target.
'0123456789'.bytesplice(0, 3, 'abc', 1, 0) # => "3456789"       # Empty source.
'0123456789'.bytesplice(0, 0, 'abc', 0, 3) # => "abc0123456789" # Empty target.

In the third form, argument range determines the target bytes and the source bytes are all of the given str:

'0123456789'.bytesplice(0..2, 'abc')  # => "abc3456789"
'0123456789'.bytesplice(3..5, 'abc')  # => "012abc6789"
'0123456789'.bytesplice(0..5, 'abc')  # => "abc6789"       # Shorter source.
'0123456789'.bytesplice(0..0, 'abc')  # => "abc123456789"  # Shorter target.
'0123456789'.bytesplice(0..2, '')     # => "3456789"       # Empty source.
'0123456789'.bytesplice(0...0, 'abc') # => "abc0123456789" # Empty target.

In the fourth form, just as in the third, arugment range determines the target bytes; argument str contains the source bytes, and the additional argument str_range determines the actual source bytes:

'0123456789'.bytesplice(0..2, 'abc', 0..2)  # => "abc3456789"
'0123456789'.bytesplice(3..5, 'abc', 0..2)  # => "012abc6789"
'0123456789'.bytesplice(0..2, 'abc', 0..1)  # => "ab3456789"     # Shorter source.
'0123456789'.bytesplice(0..1, 'abc', 0..2)  # => "abc23456789"   # Shorter target.
'0123456789'.bytesplice(0..2, 'abc', 0...0) # => "3456789"       # Empty source.
'0123456789'.bytesplice(0...0, 'abc', 0..2) # => "abc0123456789" # Empty target.

In any of the forms, the beginnings and endings of both source and target must be on character boundaries.

In these examples, self has five 3-byte characters, and so has character boundaries at offsets 0, 3, 6, 9, 12, and 15.

'こんにちは'.bytesplice(0, 3, 'abc') # => "abcんにちは"
'こんにちは'.bytesplice(1, 3, 'abc') # Raises IndexError.
'こんにちは'.bytesplice(0, 2, 'abc') # Raises IndexError.

[ GitHub ]

# File 'string.c', line 6924


static VALUE
rb_str_bytesplice(int argc, VALUE *argv, VALUE str)
{
    long beg, len, vbeg, vlen;
    VALUE val;
    int cr;

    rb_check_arity(argc, 2, 5);
    if (!(argc == 2 || argc == 3 || argc == 5)) {
        rb_raise(rb_eArgError, "wrong number of arguments (given %d, expected 2, 3, or 5)", argc);
    }
    if (argc == 2 || (argc == 3 && !RB_INTEGER_TYPE_P(argv[0]))) {
        if (!rb_range_beg_len(argv[0], &beg, &len, RSTRING_LEN(str), 2)) {
            rb_raise(rb_eTypeError, "wrong argument type %s (expected Range)",
                     rb_builtin_class_name(argv[0]));
        }
        val = argv[1];
        StringValue(val);
        if (argc == 2) {
            /* bytesplice(range, str) */
            vbeg = 0;
            vlen = RSTRING_LEN(val);
        }
        else {
            /* bytesplice(range, str, str_range) */
            if (!rb_range_beg_len(argv[2], &vbeg, &vlen, RSTRING_LEN(val), 2)) {
                rb_raise(rb_eTypeError, "wrong argument type %s (expected Range)",
                         rb_builtin_class_name(argv[2]));
            }
        }
    }
    else {
        beg = NUM2LONG(argv[0]);
        len = NUM2LONG(argv[1]);
        val = argv[2];
        StringValue(val);
        if (argc == 3) {
            /* bytesplice(index, length, str) */
            vbeg = 0;
            vlen = RSTRING_LEN(val);
        }
        else {
            /* bytesplice(index, length, str, str_index, str_length) */
            vbeg = NUM2LONG(argv[3]);
            vlen = NUM2LONG(argv[4]);
        }
    }
    str_check_beg_len(str, &beg, &len);
    str_check_beg_len(val, &vbeg, &vlen);
    str_modify_keep_cr(str);

    if (RB_UNLIKELY(ENCODING_GET_INLINED(str) != ENCODING_GET_INLINED(val))) {
        rb_enc_associate(str, rb_enc_check(str, val));
    }

    rb_str_update_1(str, beg, len, val, vbeg, vlen);
    cr = ENC_CODERANGE_AND(ENC_CODERANGE(str), ENC_CODERANGE(val));
    if (cr != ENC_CODERANGE_BROKEN)
        ENC_CODERANGE_SET(str, cr);
    return str;
}

#capitalize(mapping = :ascii) ⇒ `String`

Returns a string containing the characters in self, each with possibly changed case:

The first character is upcased.
All other characters are downcased.

Examples:

'hello world'.capitalize # => "Hello world"
'HELLO WORLD'.capitalize # => "Hello world"

Some characters do not have upcase and downcase, and so are not changed; see Case Mapping:

'1, 2, 3, ...'.capitalize # => "1, 2, 3, ..."

The casing is affected by the given mapping, which may be :ascii, :fold, or :turkic; see Case Mappings.

Related: see Converting to New String.

[ GitHub ]

# File 'string.c', line 8302


static VALUE
rb_str_capitalize(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_TITLECASE;
    VALUE ret;

    flags = check_case_options(argc, argv, flags);
    enc = str_true_enc(str);
    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return str;
    if (flags&ONIGENC_CASE_ASCII_ONLY) {
        ret = rb_str_new(0, RSTRING_LEN(str));
        rb_str_ascii_casemap(str, ret, &flags, enc);
    }
    else {
        ret = rb_str_casemap(str, &flags, enc);
    }
    return ret;
}

#capitalize!(mapping = :ascii) ⇒ `self`^?

Like #capitalize, except that:

Changes character casings in self (not in a copy of self).
Returns self if any changes are made, nil otherwise.

Related: See Modifying.

[ GitHub ]

# File 'string.c', line 8255


static VALUE
rb_str_capitalize_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_TITLECASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil;
    if (flags&ONIGENC_CASE_ASCII_ONLY)
        rb_str_ascii_casemap(str, str, &flags, enc);
    else
        str_shared_replace(str, rb_str_casemap(str, &flags, enc));

    if (ONIGENC_CASE_MODIFIED&flags) return str;
    return Qnil;
}

#casecmp(other_string) ⇒ `1`, ...

Compares self.downcase and other_string.downcase; returns:

-1 if other_string.downcase is larger.
0 if the two are equal.
1 if other_string.downcase is smaller.
nil if the two are incomparable.

Examples:

'foo'.casecmp('foo') # => 0
'foo'.casecmp('food') # => -1
'food'.casecmp('foo') # => 1
'FOO'.casecmp('foo') # => 0
'foo'.casecmp('FOO') # => 0
'foo'.casecmp(1) # => nil

See Case Mapping.

Related: #casecmp?.

[ GitHub ]

# File 'string.c', line 4342


static VALUE
rb_str_casecmp(VALUE str1, VALUE str2)
{
    VALUE s = rb_check_string_type(str2);
    if (NIL_P(s)) {
        return Qnil;
    }
    return str_casecmp(str1, s);
}

#casecmp?(other_string) ⇒ `true`, ...

Returns true if self and other_string are equal after Unicode case folding, otherwise false:

'foo'.casecmp?('foo') # => true
'foo'.casecmp?('food') # => false
'food'.casecmp?('foo') # => false
'FOO'.casecmp?('foo') # => true
'foo'.casecmp?('FOO') # => true

Returns nil if the two values are incomparable:

'foo'.casecmp?(1) # => nil

See Case Mapping.

Related: #casecmp.

[ GitHub ]

# File 'string.c', line 4432


static VALUE
rb_str_casecmp_p(VALUE str1, VALUE str2)
{
    VALUE s = rb_check_string_type(str2);
    if (NIL_P(s)) {
        return Qnil;
    }
    return str_casecmp_p(str1, s);
}

#center(size, pad_string = ' ') ⇒ `String`

Returns a centered copy of self.

If integer argument #size is greater than the size (in characters) of self, returns a new string of length #size that is a copy of self, centered and padded on both ends with pad_string:

'hello'.center(10)       # => "  hello   "
'  hello'.center(10)     # => "   hello  "
'hello'.center(10, 'ab') # => "abhelloaba"
'тест'.center(10)        # => "   тест   "
'こんにちは'.center(10)    # => "  こんにちは   "

If #size is not greater than the size of self, returns a copy of self:

'hello'.center(5)  # => "hello"
'hello'.center(1)  # => "hello"

Related: #ljust, #rjust.

[ GitHub ]

# File 'string.c', line 11125


static VALUE
rb_str_center(int argc, VALUE *argv, VALUE str)
{
    return rb_str_justify(argc, argv, str, 'c');
}

#chars ⇒ `array_of_characters`

Returns an array of the characters in self:

'hello'.chars     # => ["h", "e", "l", "l", "o"]
'тест'.chars      # => ["т", "е", "с", "т"]
'こんにちは'.chars # => ["こ", "ん", "に", "ち", "は"]

[ GitHub ]

# File 'string.c', line 9879


static VALUE
rb_str_chars(VALUE str)
{
    VALUE ary = WANTARRAY("chars", rb_str_strlen(str));
    return rb_str_enumerate_chars(str, ary);
}

#chomp(line_sep = $/) ⇒ `String`

Returns a new string copied from self, with trailing characters possibly removed:

When line_sep is "\n", removes the last one or two characters if they are "\r", "\n", or "\r\n" (but not "\n\r"):

$/                    # => "\n"
"abc\r".chomp         # => "abc"
"abc\n".chomp         # => "abc"
"abc\r\n".chomp       # => "abc"
"abc\n\r".chomp       # => "abc\n"
"тест\r\n".chomp      # => "тест"
"こんにちは\r\n".chomp  # => "こんにちは"

When line_sep is '' (an empty string), removes multiple trailing occurrences of "\n" or "\r\n" (but not "\r" or "\n\r"):

"abc\n\n\n".chomp('')           # => "abc"
"abc\r\n\r\n\r\n".chomp('')     # => "abc"
"abc\n\n\r\n\r\n\n\n".chomp('') # => "abc"
"abc\n\r\n\r\n\r".chomp('')     # => "abc\n\r\n\r\n\r"
"abc\r\r\r".chomp('')           # => "abc\r\r\r"

When line_sep is neither "\n" nor '', removes a single trailing line separator if there is one:

'abcd'.chomp('d')  # => "abc"
'abcdd'.chomp('d') # => "abcd"

[ GitHub ]

# File 'string.c', line 10343


static VALUE
rb_str_chomp(int argc, VALUE *argv, VALUE str)
{
    VALUE rs = chomp_rs(argc, argv);
    if (NIL_P(rs)) return str_duplicate(rb_cString, str);
    return rb_str_subseq(str, 0, chompped_length(str, rs));
}

#chomp!(line_sep = $/) ⇒ `self`^?

Like #chomp, but modifies self in place; returns nil if no modification made, self otherwise.

[ GitHub ]

# File 'string.c', line 10323


static VALUE
rb_str_chomp_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE rs;
    str_modifiable(str);
    if (RSTRING_LEN(str) == 0 && argc < 2) return Qnil;
    rs = chomp_rs(argc, argv);
    if (NIL_P(rs)) return Qnil;
    return rb_str_chomp_string(str, rs);
}

#chop ⇒ `String`

Returns a new string copied from self, with trailing characters possibly removed.

Removes "\r\n" if those are the last two characters.

"abc\r\n".chop      # => "abc"
"тест\r\n".chop     # => "тест"
"こんにちは\r\n".chop # => "こんにちは"

Otherwise removes the last character if it exists.

'abcd'.chop     # => "abc"
'тест'.chop     # => "тес"
'こんにちは'.chop # => "こんにち"
''.chop         # => ""

If you only need to remove the newline separator at the end of the string, #chomp is a better alternative.

[ GitHub ]

# File 'string.c', line 10170


static VALUE
rb_str_chop(VALUE str)
{
    return rb_str_subseq(str, 0, chopped_length(str));
}

#chop! ⇒ `self`^?

Like #chop, but modifies self in place; returns nil if self is empty, self otherwise.

Related: #chomp!.

[ GitHub ]

# File 'string.c', line 10144


static VALUE
rb_str_chop_bang(VALUE str)
{
    str_modify_keep_cr(str);
    if (RSTRING_LEN(str) > 0) {
        long len;
        len = chopped_length(str);
        STR_SET_LEN(str, len);
        TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str));
        if (ENC_CODERANGE(str) != ENC_CODERANGE_7BIT) {
            ENC_CODERANGE_CLEAR(str);
        }
        return str;
    }
    return Qnil;
}

#chr ⇒ `String`

Returns a string containing the first character of self:

s = 'foo' # => "foo"
s.chr     # => "f"

[ GitHub ]

# File 'string.c', line 6700


static VALUE
rb_str_chr(VALUE str)
{
    return rb_str_substr(str, 0, 1);
}

#clear ⇒ `self`

Removes the contents of self:

s = 'foo' # => "foo"
s.clear   # => ""

[ GitHub ]

# File 'string.c', line 6675


static VALUE
rb_str_clear(VALUE str)
{
    str_discard(str);
    STR_SET_EMBED(str);
    STR_SET_LEN(str, 0);
    RSTRING_PTR(str)[0] = 0;
    if (rb_enc_asciicompat(STR_ENC_GET(str)))
        ENC_CODERANGE_SET(str, ENC_CODERANGE_7BIT);
    else
        ENC_CODERANGE_SET(str, ENC_CODERANGE_VALID);
    return str;
}

#codepoints ⇒ `array_of_integers`

Returns an array of the codepoints in self; each codepoint is the integer value for a character:

'hello'.codepoints     # => [104, 101, 108, 108, 111]
'тест'.codepoints      # => [1090, 1077, 1089, 1090]
'こんにちは'.codepoints # => [12371, 12435, 12395, 12385, 12399]

[ GitHub ]

# File 'string.c', line 9939


static VALUE
rb_str_codepoints(VALUE str)
{
    VALUE ary = WANTARRAY("codepoints", rb_str_strlen(str));
    return rb_str_enumerate_codepoints(str, ary);
}

#concat(*objects) ⇒ `String`

Concatenates each object in objects to self and returns self:

s = 'foo'
s.concat('bar', 'baz') # => "foobarbaz"
s                      # => "foobarbaz"

For each given object object that is an ::Integer, the value is considered a codepoint and converted to a character before concatenation:

s = 'foo'
s.concat(32, 'bar', 32, 'baz') # => "foo bar baz"

Related: #<<, which takes a single argument.

[ GitHub ]

# File 'string.c', line 3806


static VALUE
rb_str_concat_multi(int argc, VALUE *argv, VALUE str)
{
    str_modifiable(str);

    if (argc == 1) {
        return rb_str_concat(str, argv[0]);
    }
    else if (argc > 1) {
        int i;
        VALUE arg_str = rb_str_tmp_new(0);
        rb_enc_copy(arg_str, str);
        for (i = 0; i < argc; i++) {
            rb_str_concat(arg_str, argv[i]);
        }
        rb_str_buf_append(str, arg_str);
    }

    return str;
}

#count(*selectors) ⇒ Integer

Returns the total number of characters in self that are specified by the given selectors (see Multiple Character Selectors):

a = "hello world"
a.count "lo"                   #=> 5
a.count "lo", "o"              #=> 2
a.count "hello", "^l"          #=> 4
a.count "ej-m"                 #=> 4

"hello^world".count "\\^aeiou" #=> 4
"hello-world".count "a\\-eo"   #=> 4

c = "hello world\\r\\n"
c.count "\\"                   #=> 2
c.count "\\A"                  #=> 0
c.count "X-\\w"                #=> 3

[ GitHub ]

# File 'string.c', line 9147


static VALUE
rb_str_count(int argc, VALUE *argv, VALUE str)
{
    char table[TR_TABLE_SIZE];
    rb_encoding *enc = 0;
    VALUE del = 0, nodel = 0, tstr;
    char *s, *send;
    int i;
    int ascompat;
    size_t n = 0;

    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);

    tstr = argv[0];
    StringValue(tstr);
    enc = rb_enc_check(str, tstr);
    if (argc == 1) {
        const char *ptstr;
        if (RSTRING_LEN(tstr) == 1 && rb_enc_asciicompat(enc) &&
            (ptstr = RSTRING_PTR(tstr),
             ONIGENC_IS_ALLOWED_REVERSE_MATCH(enc, (const unsigned char *)ptstr, (const unsigned char *)ptstr+1)) &&
            !is_broken_string(str)) {
            int clen;
            unsigned char c = rb_enc_codepoint_len(ptstr, ptstr+1, &clen, enc);

            s = RSTRING_PTR(str);
            if (!s || RSTRING_LEN(str) == 0) return INT2FIX(0);
            send = RSTRING_END(str);
            while (s < send) {
                if (*(unsigned char*)s++ == c) n++;
            }
            return SIZET2NUM(n);
        }
    }

    tr_setup_table(tstr, table, TRUE, &del, &nodel, enc);
    for (i=1; i<argc; i++) {
        tstr = argv[i];
        StringValue(tstr);
        enc = rb_enc_check(str, tstr);
        tr_setup_table(tstr, table, FALSE, &del, &nodel, enc);
    }

    s = RSTRING_PTR(str);
    if (!s || RSTRING_LEN(str) == 0) return INT2FIX(0);
    send = RSTRING_END(str);
    ascompat = rb_enc_asciicompat(enc);
    while (s < send) {
        unsigned int c;

        if (ascompat && (c = *(unsigned char*)s) < 0x80) {
            if (table[c]) {
                n++;
            }
            s++;
        }
        else {
            int clen;
            c = rb_enc_codepoint_len(s, send, &clen, enc);
            if (tr_find(c, table, del, nodel)) {
                n++;
            }
            s += clen;
        }
    }

    return SIZET2NUM(n);
}

#crypt(salt_str) ⇒ `String`

Returns the string generated by calling crypt(3) standard library function with str and salt_str, in this order, as its arguments. Please do not use this method any longer. It is legacy; provided only for backward compatibility with ruby scripts in earlier days. It is bad to use in contemporary programs for several reasons:

Behaviour of C’s crypt(3) depends on the OS it is run. The generated string lacks data portability.
On some OSes such as Mac OS, crypt(3) never fails (i.e. silently ends up in unexpected results).
On some OSes such as Mac OS, crypt(3) is not thread safe.
So-called “traditional” usage of crypt(3) is very very very weak. According to its manpage, Linux’s traditional crypt(3) output has only 2**56 variations; too easy to brute force today. And this is the default behaviour.
In order to make things robust some OSes implement so-called “modular” usage. To go through, you have to do a complex build-up of the salt_str parameter, by hand. Failure in generation of a proper salt string tends not to yield any errors; typos in parameters are normally not detectable.
- For instance, in the following example, the second invocation of String#crypt is wrong; it has a typo in “round=” (lacks “s”). However the call does not fail and something unexpected is generated.
```
"foo".crypt("$5$rounds=1000$salt$") # OK, proper usage
"foo".crypt("$5$round=1000$salt$")  # Typo not detected
```
Even in the “modular” mode, some hash functions are considered archaic and no longer recommended at all; for instance module $1$ is officially abandoned by its author: see

phk.freebsd.dk/sagas/md5crypt_eol/ . For another

instance module <code>$3$</code> is considered completely
broken: see the manpage of FreeBSD.

On some OS such as Mac OS, there is no modular mode. Yet, as written above, crypt(3) on Mac OS never fails. This means even if you build up a proper salt string it generates a traditional DES hash anyways, and there is no way for you to be aware of.
```
"foo".crypt("$5$rounds=1000$salt$") # => "$5fNPQMxC5j6."
```

If for some reason you cannot migrate to other secure contemporary password hashing algorithms, install the string-crypt gem and require 'string/crypt' to continue using it.

[ GitHub ]

# File 'string.c', line 10842


static VALUE
rb_str_crypt(VALUE str, VALUE salt)
{
#ifdef HAVE_CRYPT_R
    VALUE databuf;
    struct crypt_data *data;
#   define CRYPT_END() ALLOCV_END(databuf)
#else
    char *tmp_buf;
    extern char *crypt(const char *, const char *);
#   define CRYPT_END() rb_nativethread_lock_unlock(&crypt_mutex.lock)
#endif
    VALUE result;
    const char *s, *saltp;
    char *res;
#ifdef BROKEN_CRYPT
    char salt_8bit_clean[3];
#endif

    StringValue(salt);
    mustnot_wchar(str);
    mustnot_wchar(salt);
    s = StringValueCStr(str);
    saltp = RSTRING_PTR(salt);
    if (RSTRING_LEN(salt) < 2 || !saltp[0] || !saltp[1]) {
        rb_raise(rb_eArgError, "salt too short (need >=2 bytes)");
    }

#ifdef BROKEN_CRYPT
    if (!ISASCII((unsigned char)saltp[0]) || !ISASCII((unsigned char)saltp[1])) {
        salt_8bit_clean[0] = saltp[0] & 0x7f;
        salt_8bit_clean[1] = saltp[1] & 0x7f;
        salt_8bit_clean[2] = '\0';
        saltp = salt_8bit_clean;
    }
#endif
#ifdef HAVE_CRYPT_R
    data = ALLOCV(databuf, sizeof(struct crypt_data));
# ifdef HAVE_STRUCT_CRYPT_DATA_INITIALIZED
    data->initialized = 0;
# endif
    res = crypt_r(s, saltp, data);
#else
    rb_nativethread_lock_lock(&crypt_mutex.lock);
    res = crypt(s, saltp);
#endif
    if (!res) {
        int err = errno;
        CRYPT_END();
        rb_syserr_fail(err, "crypt");
    }
#ifdef HAVE_CRYPT_R
    result = rb_str_new_cstr(res);
    CRYPT_END();
#else
    // We need to copy this buffer because it's static and we need to unlock the mutex
    // before allocating a new object (the string to be returned). If we allocate while
    // holding the lock, we could run GC which fires the VM barrier and causes a deadlock
    // if other ractors are waiting on this lock.
    size_t res_size = strlen(res)+1;
    tmp_buf = ALLOCA_N(char, res_size); // should be small enough to alloca
    memcpy(tmp_buf, res, res_size);
    res = tmp_buf;
    CRYPT_END();
    result = rb_str_new_cstr(res);
#endif
    return result;
}

#- ⇒ `String` #dedup ⇒ `String`

Alias for #-@.

#delete(*selectors) ⇒ `String`

Returns a copy of self with characters specified by selectors removed (see Multiple Character Selectors):

"hello".delete "l","lo"        #=> "heo"
"hello".delete "lo"            #=> "he"
"hello".delete "aeiou", "^e"   #=> "hell"
"hello".delete "ej-m"          #=> "ho"

[ GitHub ]

# File 'string.c', line 8964


static VALUE
rb_str_delete(int argc, VALUE *argv, VALUE str)
{
    str = str_duplicate(rb_cString, str);
    rb_str_delete_bang(argc, argv, str);
    return str;
}

#delete!(*selectors) ⇒ `self`^?

Like #delete, but modifies self in place. Returns self if any changes were made, nil otherwise.

[ GitHub ]

# File 'string.c', line 8888


static VALUE
rb_str_delete_bang(int argc, VALUE *argv, VALUE str)
{
    char squeez[TR_TABLE_SIZE];
    rb_encoding *enc = 0;
    char *s, *send, *t;
    VALUE del = 0, nodel = 0;
    int modify = 0;
    int i, ascompat, cr;

    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil;
    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
    for (i=0; i<argc; i++) {
        VALUE s = argv[i];

        StringValue(s);
        enc = rb_enc_check(str, s);
        tr_setup_table(s, squeez, i==0, &del, &nodel, enc);
    }

    str_modify_keep_cr(str);
    ascompat = rb_enc_asciicompat(enc);
    s = t = RSTRING_PTR(str);
    send = RSTRING_END(str);
    cr = ascompat ? ENC_CODERANGE_7BIT : ENC_CODERANGE_VALID;
    while (s < send) {
        unsigned int c;
        int clen;

        if (ascompat && (c = *(unsigned char*)s) < 0x80) {
            if (squeez[c]) {
                modify = 1;
            }
            else {
                if (t != s) *t = c;
                t++;
            }
            s++;
        }
        else {
            c = rb_enc_codepoint_len(s, send, &clen, enc);

            if (tr_find(c, squeez, del, nodel)) {
                modify = 1;
            }
            else {
                if (t != s) rb_enc_mbcput(c, t, enc);
                t += clen;
                if (cr == ENC_CODERANGE_7BIT) cr = ENC_CODERANGE_VALID;
            }
            s += clen;
        }
    }
    TERM_FILL(t, TERM_LEN(str));
    STR_SET_LEN(str, t - RSTRING_PTR(str));
    ENC_CODERANGE_SET(str, cr);

    if (modify) return str;
    return Qnil;
}

#delete_prefix(prefix) ⇒ `String`

Returns a copy of self with leading substring prefix removed:

'hello'.delete_prefix('hel')      # => "lo"
'hello'.delete_prefix('llo')      # => "hello"
'тест'.delete_prefix('те')        # => "ст"
'こんにちは'.delete_prefix('こん')  # => "にちは"

[ GitHub ]

# File 'string.c', line 11360


static VALUE
rb_str_delete_prefix(VALUE str, VALUE prefix)
{
    long prefixlen;

    prefixlen = deleted_prefix_length(str, prefix);
    if (prefixlen <= 0) return str_duplicate(rb_cString, str);

    return rb_str_subseq(str, prefixlen, RSTRING_LEN(str) - prefixlen);
}

#delete_prefix!(prefix) ⇒ `self`^?

Like #delete_prefix, except that self is modified in place. Returns self if the prefix is removed, nil otherwise.

[ GitHub ]

# File 'string.c', line 11340


static VALUE
rb_str_delete_prefix_bang(VALUE str, VALUE prefix)
{
    long prefixlen;
    str_modify_keep_cr(str);

    prefixlen = deleted_prefix_length(str, prefix);
    if (prefixlen <= 0) return Qnil;

    return rb_str_drop_bytes(str, prefixlen);
}

#delete_suffix(suffix) ⇒ `String`

Returns a copy of self with trailing substring suffix removed:

'hello'.delete_suffix('llo')      # => "he"
'hello'.delete_suffix('hel')      # => "hello"
'тест'.delete_suffix('ст')        # => "те"
'こんにちは'.delete_suffix('ちは')  # => "こんに"

[ GitHub ]

# File 'string.c', line 11443


static VALUE
rb_str_delete_suffix(VALUE str, VALUE suffix)
{
    long suffixlen;

    suffixlen = deleted_suffix_length(str, suffix);
    if (suffixlen <= 0) return str_duplicate(rb_cString, str);

    return rb_str_subseq(str, 0, RSTRING_LEN(str) - suffixlen);
}

#delete_suffix!(suffix) ⇒ `self`^?

Like #delete_suffix, except that self is modified in place. Returns self if the suffix is removed, nil otherwise.

[ GitHub ]

# File 'string.c', line 11415


static VALUE
rb_str_delete_suffix_bang(VALUE str, VALUE suffix)
{
    long olen, suffixlen, len;
    str_modifiable(str);

    suffixlen = deleted_suffix_length(str, suffix);
    if (suffixlen <= 0) return Qnil;

    olen = RSTRING_LEN(str);
    str_modify_keep_cr(str);
    len = olen - suffixlen;
    STR_SET_LEN(str, len);
    TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str));
    if (ENC_CODERANGE(str) != ENC_CODERANGE_7BIT) {
        ENC_CODERANGE_CLEAR(str);
    }
    return str;
}

#downcase(mapping) ⇒ `String`

Returns a string containing the downcased characters in self:

s = 'Hello World!' # => "Hello World!"
s.downcase         # => "hello world!"

The casing may be affected by the given mapping; see Case Mapping.

Related: #downcase!, #upcase, #upcase!.

[ GitHub ]

# File 'string.c', line 8217


static VALUE
rb_str_downcase(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_DOWNCASE;
    VALUE ret;

    flags = check_case_options(argc, argv, flags);
    enc = str_true_enc(str);
    if (case_option_single_p(flags, enc, str)) {
        ret = rb_str_new(RSTRING_PTR(str), RSTRING_LEN(str));
        str_enc_copy_direct(ret, str);
        downcase_single(ret);
    }
    else if (flags&ONIGENC_CASE_ASCII_ONLY) {
        ret = rb_str_new(0, RSTRING_LEN(str));
        rb_str_ascii_casemap(str, ret, &flags, enc);
    }
    else {
        ret = rb_str_casemap(str, &flags, enc);
    }

    return ret;
}

#downcase!(mapping) ⇒ `self`^?

Downcases the characters in self; returns self if any changes were made, nil otherwise:

s = 'Hello World!' # => "Hello World!"
s.downcase!        # => "hello world!"
s                  # => "hello world!"
s.downcase!        # => nil

The casing may be affected by the given mapping; see Case Mapping.

Related: #downcase, #upcase, #upcase!.

[ GitHub ]

# File 'string.c', line 8178


static VALUE
rb_str_downcase_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_DOWNCASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (case_option_single_p(flags, enc, str)) {
        if (downcase_single(str))
            flags |= ONIGENC_CASE_MODIFIED;
    }
    else if (flags&ONIGENC_CASE_ASCII_ONLY)
        rb_str_ascii_casemap(str, str, &flags, enc);
    else
        str_shared_replace(str, rb_str_casemap(str, &flags, enc));

    if (ONIGENC_CASE_MODIFIED&flags) return str;
    return Qnil;
}

#dump ⇒ `String`

Returns a printable version of self, enclosed in double-quotes, with special characters escaped, and with non-printing characters replaced by hexadecimal notation:

"hello \n ''".dump    # => "\"hello \\n ''\""
"\f\x00\xff\\\"".dump # => "\"\\f\\x00\\xFF\\\\\\\"\""

Related: #undump (inverse of dump).

[ GitHub ]

# File 'string.c', line 7442


VALUE
rb_str_dump(VALUE str)
{
    int encidx = rb_enc_get_index(str);
    rb_encoding *enc = rb_enc_from_index(encidx);
    long len;
    const char *p, *pend;
    char *q, *qend;
    VALUE result;
    int u8 = (encidx == rb_utf8_encindex());
    static const char nonascii_suffix[] = ".dup.force_encoding(\"%s\")";

    len = 2;			/* "" */
    if (!rb_enc_asciicompat(enc)) {
        len += strlen(nonascii_suffix) - rb_strlen_lit("%s");
        len += strlen(enc->name);
    }

    p = RSTRING_PTR(str); pend = p + RSTRING_LEN(str);
    while (p < pend) {
        int clen;
        unsigned char c = *p++;

        switch (c) {
          case '"':  case '\\':
          case '\n': case '\r':
          case '\t': case '\f':
          case '\013': case '\010': case '\007': case '\033':
            clen = 2;
            break;

          case '#':
            clen = IS_EVSTR(p, pend) ? 2 : 1;
            break;

          default:
            if (ISPRINT(c)) {
                clen = 1;
            }
            else {
                if (u8 && c > 0x7F) {	/* \u notation */
                    int n = rb_enc_precise_mbclen(p-1, pend, enc);
                    if (MBCLEN_CHARFOUND_P(n)) {
                        unsigned int cc = rb_enc_mbc_to_codepoint(p-1, pend, enc);
                        if (cc <= 0xFFFF)
                            clen = 6;  /* \uXXXX */
                        else if (cc <= 0xFFFFF)
                            clen = 9;  /* \u{XXXXX} */
                        else
                            clen = 10; /* \u{XXXXXX} */
                        p += MBCLEN_CHARFOUND_LEN(n)-1;
                        break;
                    }
                }
                clen = 4;	/* \xNN */
            }
            break;
        }

        if (clen > LONG_MAX - len) {
            rb_raise(rb_eRuntimeError, "string size too big");
        }
        len += clen;
    }

    result = rb_str_new(0, len);
    p = RSTRING_PTR(str); pend = p + RSTRING_LEN(str);
    q = RSTRING_PTR(result); qend = q + len + 1;

    *q++ = '"';
    while (p < pend) {
        unsigned char c = *p++;

        if (c == '"' || c == '\\') {
            *q++ = '\\';
            *q++ = c;
        }
        else if (c == '#') {
            if (IS_EVSTR(p, pend)) *q++ = '\\';
            *q++ = '#';
        }
        else if (c == '\n') {
            *q++ = '\\';
            *q++ = 'n';
        }
        else if (c == '\r') {
            *q++ = '\\';
            *q++ = 'r';
        }
        else if (c == '\t') {
            *q++ = '\\';
            *q++ = 't';
        }
        else if (c == '\f') {
            *q++ = '\\';
            *q++ = 'f';
        }
        else if (c == '\013') {
            *q++ = '\\';
            *q++ = 'v';
        }
        else if (c == '\010') {
            *q++ = '\\';
            *q++ = 'b';
        }
        else if (c == '\007') {
            *q++ = '\\';
            *q++ = 'a';
        }
        else if (c == '\033') {
            *q++ = '\\';
            *q++ = 'e';
        }
        else if (ISPRINT(c)) {
            *q++ = c;
        }
        else {
            *q++ = '\\';
            if (u8) {
                int n = rb_enc_precise_mbclen(p-1, pend, enc) - 1;
                if (MBCLEN_CHARFOUND_P(n)) {
                    int cc = rb_enc_mbc_to_codepoint(p-1, pend, enc);
                    p += n;
                    if (cc <= 0xFFFF)
                        snprintf(q, qend-q, "u%04X", cc);    /* \uXXXX */
                    else
                        snprintf(q, qend-q, "u{%X}", cc);  /* \u{XXXXX} or \u{XXXXXX} */
                    q += strlen(q);
                    continue;
                }
            }
            snprintf(q, qend-q, "x%02X", c);
            q += 3;
        }
    }
    *q++ = '"';
    *q = '\0';
    if (!rb_enc_asciicompat(enc)) {
        snprintf(q, qend-q, nonascii_suffix, enc->name);
        encidx = rb_ascii8bit_encindex();
    }
    /* result from dump is ASCII */
    rb_enc_associate_index(result, encidx);
    ENC_CODERANGE_SET(result, ENC_CODERANGE_7BIT);
    return result;
}

#dup

This method is for internal use only.

[ GitHub ]

# File 'string.c', line 1961


VALUE
rb_str_dup_m(VALUE str)
{
    if (LIKELY(BARE_STRING_P(str))) {
        return str_duplicate(rb_cString, str);
    }
    else {
        return rb_obj_dup(str);
    }
}

#each_byte {|byte| ... } ⇒ `self` #each_byte ⇒ Enumerator

Calls the given block with each successive byte from self; returns self:

'hello'.each_byte {|byte| print byte, ' ' }
print "\n"
'тест'.each_byte {|byte| print byte, ' ' }
print "\n"
'こんにちは'.each_byte {|byte| print byte, ' ' }
print "\n"

Output:

104 101 108 108 111
209 130 208 181 209 129 209 130
227 129 147 227 130 147 227 129 171 227 129 161 227 129 175

Returns an enumerator if no block is given.

[ GitHub ]

# File 'string.c', line 9795


static VALUE
rb_str_each_byte(VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_byte_size);
    return rb_str_enumerate_bytes(str, 0);
}

#each_char {|c| ... } ⇒ `self` #each_char ⇒ Enumerator

Calls the given block with each successive character from self; returns self:

'hello'.each_char {|char| print char, ' ' }
print "\n"
'тест'.each_char {|char| print char, ' ' }
print "\n"
'こんにちは'.each_char {|char| print char, ' ' }
print "\n"

Output:

h e l l o
т е с т
こ ん に ち は

Returns an enumerator if no block is given.

[ GitHub ]

# File 'string.c', line 9864


static VALUE
rb_str_each_char(VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_char_size);
    return rb_str_enumerate_chars(str, 0);
}

#each_codepoint {|integer| ... } ⇒ `self` #each_codepoint ⇒ Enumerator

Calls the given block with each successive codepoint from self; each codepoint is the integer value for a character; returns self:

'hello'.each_codepoint {|codepoint| print codepoint, ' ' }
print "\n"
'тест'.each_codepoint {|codepoint| print codepoint, ' ' }
print "\n"
'こんにちは'.each_codepoint {|codepoint| print codepoint, ' ' }
print "\n"

Output:

104 101 108 108 111
1090 1077 1089 1090
12371 12435 12395 12385 12399

Returns an enumerator if no block is given.

[ GitHub ]

# File 'string.c', line 9924


static VALUE
rb_str_each_codepoint(VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_char_size);
    return rb_str_enumerate_codepoints(str, 0);
}

#each_grapheme_cluster {|gc| ... } ⇒ `self` #each_grapheme_cluster ⇒ Enumerator

Calls the given block with each successive grapheme cluster from self (see Unicode Grapheme Cluster Boundaries); returns self:

s = "\u0061\u0308-pqr-\u0062\u0308-xyz-\u0063\u0308" # => "ä-pqr-b̈-xyz-c̈"
s.each_grapheme_cluster {|gc| print gc, ' ' }

Output:

ä - p q r - b̈ - x y z - c̈

Returns an enumerator if no block is given.

[ GitHub ]

# File 'string.c', line 10094


static VALUE
rb_str_each_grapheme_cluster(VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_grapheme_cluster_size);
    return rb_str_enumerate_grapheme_clusters(str, 0);
}

#each_line(line_sep = $/, chomp: false) {|substring| ... } ⇒ `self` #each_line(line_sep = $/, chomp: false) ⇒ Enumerator

With a block given, forms the substrings (“lines”) that are the result of splitting self at each occurrence of the given line separator line_sep; passes each line to the block; returns self:

s = <<~EOT
This is the first line.
This is line two.

This is line four.
This is line five.
EOT

s.each_line {|line| p line }

Output:

"This is the first line.\n"
"This is line two.\n"
"\n"
"This is line four.\n"
"This is line five.\n"

With a different line_sep:

s.each_line(' is ') {|line| p line }

Output:

"This is "
"the first line.\nThis is "
"line two.\n\nThis is "
"line four.\nThis is "
"line five.\n"

With #chomp as true, removes the trailing line_sep from each line:

s.each_line(chomp: true) {|line| p line }

Output:

"This is the first line."
"This is line two."
""
"This is line four."
"This is line five."

With an empty string as line_sep, forms and passes “paragraphs” by splitting at each occurrence of two or more newlines:

s.each_line('') {|line| p line }

Output:

"This is the first line.\nThis is line two.\n\n"
"This is line four.\nThis is line five.\n"

With no block given, returns an enumerator.

[ GitHub ]

# File 'string.c', line 9743


static VALUE
rb_str_each_line(int argc, VALUE *argv, VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, argc, argv, 0);
    return rb_str_enumerate_lines(argc, argv, str, 0);
}

#encode(dst_encoding = Encoding.default_internal, enc_opts) ⇒ `String` #encode(dst_encoding, src_encoding, enc_opts) ⇒ `String`

Returns a copy of self transcoded as determined by dst_encoding. By default, raises an exception if self contains an invalid byte or a character not defined in dst_encoding; that behavior may be modified by encoding options; see below.

With no arguments:

Uses the same encoding if Encoding.default_internal is nil (the default):

Encoding.default_internal # => nil
s = "Ruby\x99".force_encoding('Windows-1252')
s.encoding                # => #<Encoding:Windows-1252>
s.bytes                   # => [82, 117, 98, 121, 153]
t = s.encode              # => "Ruby\x99"
t.encoding                # => #<Encoding:Windows-1252>
t.bytes                   # => [82, 117, 98, 121, 226, 132, 162]

Otherwise, uses the encoding Encoding.default_internal:

Encoding.default_internal = 'UTF-8'
t = s.encode              # => "Ruby™"
t.encoding                # => #<Encoding:UTF-8>

With only argument dst_encoding given, uses that encoding:

s = "Ruby\x99".force_encoding('Windows-1252')
s.encoding            # => #<Encoding:Windows-1252>
t = s.encode('UTF-8') # => "Ruby™"
t.encoding            # => #<Encoding:UTF-8>

With arguments dst_encoding and src_encoding given, interprets self using src_encoding, encodes the new string using dst_encoding:

s = "Ruby\x99"
t = s.encode('UTF-8', 'Windows-1252') # => "Ruby™"
t.encoding                            # => #<Encoding:UTF-8>

Optional keyword arguments enc_opts specify encoding options; see {Encoding Options}.

Please note that, unless invalid: :replace option is given, conversion from an encoding enc to the same encoding enc (independent of whether enc is given explicitly or implicitly) is a no-op, i.e. the string is simply copied without any changes, and no exceptions are raised, even if there are invalid bytes.

[ GitHub ]

# File 'transcode.c', line 2925


static VALUE
str_encode(int argc, VALUE *argv, VALUE str)
{
    VALUE newstr = str;
    int encidx = str_transcode(argc, argv, &newstr);
    return encoded_dup(newstr, str, encidx);
}

#encode!(dst_encoding = Encoding.default_internal, enc_opts) ⇒ `self` #encode!(dst_encoding, src_encoding, enc_opts) ⇒ `self`

Like #encode, but applies encoding changes to self; returns self.

[ GitHub ]

# File 'transcode.c', line 2894


static VALUE
str_encode_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE newstr;
    int encidx;

    rb_check_frozen(str);

    newstr = str;
    encidx = str_transcode(argc, argv, &newstr);

    if (encidx < 0) return str;
    if (newstr == str) {
        rb_enc_associate_index(str, encidx);
        return str;
    }
    rb_str_shared_replace(str, newstr);
    return str_encode_associate(str, encidx);
}

#encoding ⇒ Encoding

Alias for Regexp#encoding.

#end_with?(*strings) ⇒ `Boolean`

Returns whether self ends with any of the given strings.

Returns true if any given string matches the end, false otherwise:

'hello'.end_with?('ello')               #=> true
'hello'.end_with?('heaven', 'ello')     #=> true
'hello'.end_with?('heaven', 'paradise') #=> false
'тест'.end_with?('т')                   # => true
'こんにちは'.end_with?('は')              # => true

Related: #start_with?.

[ GitHub ]

# File 'string.c', line 11256


static VALUE
rb_str_end_with(int argc, VALUE *argv, VALUE str)
{
    int i;

    for (i=0; i<argc; i++) {
        VALUE tmp = argv[i];
        const char *p, *s, *e;
        long slen, tlen;
        rb_encoding *enc;

        StringValue(tmp);
        enc = rb_enc_check(str, tmp);
        if ((tlen = RSTRING_LEN(tmp)) == 0) return Qtrue;
        if ((slen = RSTRING_LEN(str)) < tlen) continue;
        p = RSTRING_PTR(str);
        e = p + slen;
        s = e - tlen;
        if (!at_char_boundary(p, s, e, enc))
            continue;
        if (memcmp(s, RSTRING_PTR(tmp), tlen) == 0)
            return Qtrue;
    }
    return Qfalse;
}

#eql?(object) ⇒ `Boolean`

Returns true if object has the same length and content; as self; false otherwise:

s = 'foo'
s.eql?('foo') # => true
s.eql?('food') # => false
s.eql?('FOO') # => false

Returns false if the two strings’ encodings are not compatible:

"\u{e4 f6 fc}".encode(Encoding::ISO_8859_1).eql?("\u{c4 d6 dc}") # => false

[ GitHub ]

# File 'string.c', line 4270


VALUE
rb_str_eql(VALUE str1, VALUE str2)
{
    if (str1 == str2) return Qtrue;
    if (!RB_TYPE_P(str2, T_STRING)) return Qfalse;
    return rb_str_eql_internal(str1, str2);
}

#force_encoding(encoding) ⇒ `self`

Changes the encoding of self to #encoding, which may be a string encoding name or an ::Encoding object; returns self:

s = 'łał'
s.bytes                   # => [197, 130, 97, 197, 130]
s.encoding                # => #<Encoding:UTF-8>
s.force_encoding('ascii') # => "\xC5\x82a\xC5\x82"
s.encoding                # => #<Encoding:US-ASCII>

Does not change the underlying bytes:

s.bytes                   # => [197, 130, 97, 197, 130]

Makes the change even if the given #encoding is invalid for self (as is the change above):

s.valid_encoding?                 # => false
s.force_encoding(Encoding::UTF_8) # => "łał"
s.valid_encoding?                 # => true

[ GitHub ]

# File 'string.c', line 11487


static VALUE
rb_str_force_encoding(VALUE str, VALUE enc)
{
    str_modifiable(str);

    rb_encoding *encoding = rb_to_encoding(enc);
    int idx = rb_enc_to_index(encoding);

    // If the encoding is unchanged, we do nothing.
    if (ENCODING_GET(str) == idx) {
        return str;
    }

    rb_enc_associate_index(str, idx);

    // If the coderange was 7bit and the new encoding is ASCII-compatible
    // we can keep the coderange.
    if (ENC_CODERANGE(str) == ENC_CODERANGE_7BIT && encoding && rb_enc_asciicompat(encoding)) {
        return str;
    }

    ENC_CODERANGE_CLEAR(str);
    return str;
}

#freeze

This method is for internal use only.

[ GitHub ]

# File 'string.c', line 3235


VALUE
rb_str_freeze(VALUE str)
{
    if (CHILLED_STRING_P(str)) {
        FL_UNSET_RAW(str, STR_CHILLED);
    }

    if (OBJ_FROZEN(str)) return str;
    rb_str_resize(str, RSTRING_LEN(str));
    return rb_obj_freeze(str);
}

#getbyte(index) ⇒ Integer^?

Returns the byte at zero-based #index as an integer, or nil if #index is out of range:

s = 'abcde'   # => "abcde"
s.getbyte(0)  # => 97
s.getbyte(-1) # => 101
s.getbyte(5)  # => nil

Related: #setbyte.

[ GitHub ]

# File 'string.c', line 6719


VALUE
rb_str_getbyte(VALUE str, VALUE index)
{
    long pos = NUM2LONG(index);

    if (pos < 0)
        pos += RSTRING_LEN(str);
    if (pos < 0 ||  RSTRING_LEN(str) <= pos)
        return Qnil;

    return INT2FIX((unsigned char)RSTRING_PTR(str)[pos]);
}

#grapheme_clusters ⇒ `array_of_grapheme_clusters`

Returns an array of the grapheme clusters in self (see Unicode Grapheme Cluster Boundaries):

s = "\u0061\u0308-pqr-\u0062\u0308-xyz-\u0063\u0308" # => "ä-pqr-b̈-xyz-c̈"
s.grapheme_clusters
# => ["ä", "-", "p", "q", "r", "-", "b̈", "-", "x", "y", "z", "-", "c̈"]

[ GitHub ]

# File 'string.c', line 10109


static VALUE
rb_str_grapheme_clusters(VALUE str)
{
    VALUE ary = WANTARRAY("grapheme_clusters", rb_str_strlen(str));
    return rb_str_enumerate_grapheme_clusters(str, ary);
}

#gsub(pattern, replacement) ⇒ `String` #gsub(pattern) {|match| ... } ⇒ `String` #gsub(pattern) ⇒ Enumerator

Returns a copy of self with all occurrences of the given pattern replaced.

See Substitution Methods.

Returns an ::Enumerator if no replacement and no block given.

Related: #sub, #sub!, #gsub!.

[ GitHub ]

# File 'string.c', line 6635


static VALUE
rb_str_gsub(int argc, VALUE *argv, VALUE str)
{
    return str_gsub(argc, argv, str, 0);
}

#gsub!(pattern, replacement) ⇒ `self`^? #gsub!(pattern) {|match| ... } ⇒ `self`^? #gsub!(pattern) ⇒ Enumerator

Performs the specified substring replacement(s) on self; returns self if any replacement occurred, nil otherwise.

See Substitution Methods.

Returns an ::Enumerator if no replacement and no block given.

Related: #sub, #gsub, #sub!.

[ GitHub ]

# File 'string.c', line 6611


static VALUE
rb_str_gsub_bang(int argc, VALUE *argv, VALUE str)
{
    str_modify_keep_cr(str);
    return str_gsub(argc, argv, str, 1);
}

#hash ⇒ Integer

Returns the integer hash value for self. The value is based on the length, content and encoding of self.

Related: Object#hash.

[ GitHub ]

# File 'string.c', line 4152


static VALUE
rb_str_hash_m(VALUE str)
{
    st_index_t hval = rb_str_hash(str);
    return ST2FIX(hval);
}

#hex ⇒ Integer

Interprets the leading substring of self as a string of hexadecimal digits (with an optional sign and an optional 0x) and returns the corresponding number; returns zero if there is no such leading substring:

'0x0a'.hex        # => 10
'-1234'.hex       # => -4660
'0'.hex           # => 0
'non-numeric'.hex # => 0

Related: #oct.

[ GitHub ]

# File 'string.c', line 10740


static VALUE
rb_str_hex(VALUE str)
{
    return rb_str_to_inum(str, 16, FALSE);
}

#include?(other_string) ⇒ `Boolean`

Returns true if self contains other_string, false otherwise:

s = 'foo'
s.include?('f')    # => true
s.include?('fo')   # => true
s.include?('food') # => false

[ GitHub ]

# File 'string.c', line 7099


VALUE
rb_str_include(VALUE str, VALUE arg)
{
    long i;

    StringValue(arg);
    i = rb_str_index(str, arg, 0);

    return RBOOL(i != -1);
}

#index(substring, offset = 0) ⇒ Integer^? #index(regexp, offset = 0) ⇒ Integer^?

Returns the integer index of the first match for the given argument, or nil if none found; the search of self is forward, and begins at position offset (in characters).

With string argument substring, returns the index of the first matching substring in self:

'foo'.index('f')         # => 0
'foo'.index('o')         # => 1
'foo'.index('oo')        # => 1
'foo'.index('ooo')       # => nil
'тест'.index('с')        # => 2
'こんにちは'.index('ち')   # => 3

With Regexp argument regexp, returns the index of the first match in self:

'foo'.index(/o./) # => 1
'foo'.index(/.o/) # => 0

With positive integer offset, begins the search at position offset:

'foo'.index('o', 1)        # => 1
'foo'.index('o', 2)        # => 2
'foo'.index('o', 3)        # => nil
'тест'.index('с', 1)       # => 2
'こんにちは'.index('ち', 2)  # => 3

With negative integer offset, selects the search position by counting backward from the end of self:

'foo'.index('o', -1)  # => 2
'foo'.index('o', -2)  # => 1
'foo'.index('o', -3)  # => 1
'foo'.index('o', -4)  # => nil
'foo'.index(/o./, -2) # => 1
'foo'.index(/.o/, -2) # => 1

Related: #rindex.

[ GitHub ]

# File 'string.c', line 4532


static VALUE
rb_str_index_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE initpos;
    rb_encoding *enc = STR_ENC_GET(str);
    long pos;

    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
        long slen = str_strlen(str, enc); /* str's enc */
        pos = NUM2LONG(initpos);
        if (pos < 0 ? (pos += slen) < 0 : pos > slen) {
            if (RB_TYPE_P(sub, T_REGEXP)) {
                rb_backref_set(Qnil);
            }
            return Qnil;
        }
    }
    else {
        pos = 0;
    }

    if (RB_TYPE_P(sub, T_REGEXP)) {
        pos = str_offset(RSTRING_PTR(str), RSTRING_END(str), pos,
                         enc, single_byte_optimizable(str));

        if (rb_reg_search(sub, str, pos, 0) >= 0) {
            VALUE match = rb_backref_get();
            struct re_registers *regs = RMATCH_REGS(match);
            pos = rb_str_sublen(str, BEG(0));
            return LONG2NUM(pos);
        }
    }
    else {
        StringValue(sub);
        pos = rb_str_index(str, sub, pos);
        if (pos >= 0) {
            pos = rb_str_sublen(str, pos);
            return LONG2NUM(pos);
        }
    }
    return Qnil;
}

#replace(other_string) ⇒ `self` #initialize_copy(other_string) ⇒ `self`

Alias for #replace.

#insert(index, other_string) ⇒ `self`

Inserts the given other_string into self; returns self.

If the ::Integer #index is positive, inserts other_string at offset #index:

'foo'.insert(1, 'bar') # => "fbaroo"

If the ::Integer #index is negative, counts backward from the end of self and inserts other_string at offset #index1</tt> (that is, after self[index]):

'foo'.insert(-2, 'bar') # => "fobaro"

[ GitHub ]

# File 'string.c', line 6099


static VALUE
rb_str_insert(VALUE str, VALUE idx, VALUE str2)
{
    long pos = NUM2LONG(idx);

    if (pos == -1) {
        return rb_str_append(str, str2);
    }
    else if (pos < 0) {
        pos++;
    }
    rb_str_update(str, pos, 0, str2);
    return str;
}

#inspect ⇒ `String`

Returns a printable version of self, enclosed in double-quotes, and with special characters escaped:

s = "foo\tbar\tbaz\n"
s.inspect
# => "\"foo\\tbar\\tbaz\\n\""

[ GitHub ]

# File 'string.c', line 7328


VALUE
rb_str_inspect(VALUE str)
{
    int encidx = ENCODING_GET(str);
    rb_encoding *enc = rb_enc_from_index(encidx);
    const char *p, *pend, *prev;
    char buf[CHAR_ESC_LEN + 1];
    VALUE result = rb_str_buf_new(0);
    rb_encoding *resenc = rb_default_internal_encoding();
    int unicode_p = rb_enc_unicode_p(enc);
    int asciicompat = rb_enc_asciicompat(enc);

    if (resenc == NULL) resenc = rb_default_external_encoding();
    if (!rb_enc_asciicompat(resenc)) resenc = rb_usascii_encoding();
    rb_enc_associate(result, resenc);
    str_buf_cat2(result, "\"");

    p = RSTRING_PTR(str); pend = RSTRING_END(str);
    prev = p;
    while (p < pend) {
        unsigned int c, cc;
        int n;

        n = rb_enc_precise_mbclen(p, pend, enc);
        if (!MBCLEN_CHARFOUND_P(n)) {
            if (p > prev) str_buf_cat(result, prev, p - prev);
            n = rb_enc_mbminlen(enc);
            if (pend < p + n)
                n = (int)(pend - p);
            while (n--) {
                snprintf(buf, CHAR_ESC_LEN, "\\x%02X", *p & 0377);
                str_buf_cat(result, buf, strlen(buf));
                prev = ++p;
            }
            continue;
        }
        n = MBCLEN_CHARFOUND_LEN(n);
        c = rb_enc_mbc_to_codepoint(p, pend, enc);
        p += n;
        if ((asciicompat || unicode_p) &&
          (c == '"'|| c == '\\' ||
            (c == '#' &&
             p < pend &&
             MBCLEN_CHARFOUND_P(rb_enc_precise_mbclen(p,pend,enc)) &&
             (cc = rb_enc_codepoint(p,pend,enc),
              (cc == '$' || cc == '@' || cc == '{'))))) {
            if (p - n > prev) str_buf_cat(result, prev, p - n - prev);
            str_buf_cat2(result, "\\");
            if (asciicompat || enc == resenc) {
                prev = p - n;
                continue;
            }
        }
        switch (c) {
          case '\n': cc = 'n'; break;
          case '\r': cc = 'r'; break;
          case '\t': cc = 't'; break;
          case '\f': cc = 'f'; break;
          case '\013': cc = 'v'; break;
          case '\010': cc = 'b'; break;
          case '\007': cc = 'a'; break;
          case 033: cc = 'e'; break;
          default: cc = 0; break;
        }
        if (cc) {
            if (p - n > prev) str_buf_cat(result, prev, p - n - prev);
            buf[0] = '\\';
            buf[1] = (char)cc;
            str_buf_cat(result, buf, 2);
            prev = p;
            continue;
        }
        /* The special casing of 0x85 (NEXT_LINE) here is because
         * Oniguruma historically treats it as printable, but it
         * doesn't match the print POSIX bracket class or character
         * property in regexps.
         *
         * See Ruby Bug #16842 for details:
         * https://bugs.ruby-lang.org/issues/16842
         */
        if ((enc == resenc && rb_enc_isprint(c, enc) && c != 0x85) ||
            (asciicompat && rb_enc_isascii(c, enc) && ISPRINT(c))) {
            continue;
        }
        else {
            if (p - n > prev) str_buf_cat(result, prev, p - n - prev);
            rb_str_buf_cat_escaped_char(result, c, unicode_p);
            prev = p;
            continue;
        }
    }
    if (p > prev) str_buf_cat(result, prev, p - prev);
    str_buf_cat2(result, "\"");

    return result;
}

#intern ⇒ Symbol #to_sym ⇒ Symbol
Also known as: #to_sym

Returns the ::Symbol corresponding to str, creating the symbol if it did not previously exist. See Symbol#id2name.

"Koala".intern         #=> :Koala
s = 'cat'.to_sym       #=> :cat
s == :cat              #=> true
s = '@cat'.to_sym      #=> :@cat
s == :@cat             #=> true

This can also be used to create symbols that cannot be represented using the :xxx notation.

'cat and dog'.to_sym   #=> :"cat and dog"

[ GitHub ]

# File 'symbol.c', line 910


VALUE
rb_str_intern(VALUE str)
{
    VALUE sym = 0;

    GLOBAL_SYMBOLS_LOCKING(symbols) {
        sym = lookup_str_sym_with_lock(symbols, str);

        if (sym) {
            // ok
        }
        else if (USE_SYMBOL_GC) {
            rb_encoding *enc = rb_enc_get(str);
            rb_encoding *ascii = rb_usascii_encoding();
            if (enc != ascii && sym_check_asciionly(str, false)) {
                str = rb_str_dup(str);
                rb_enc_associate(str, ascii);
                OBJ_FREEZE(str);
                enc = ascii;
            }
            else {
                str = rb_str_dup(str);
                OBJ_FREEZE(str);
            }
            str = rb_fstring(str);
            int type = rb_str_symname_type(str, IDSET_ATTRSET_FOR_INTERN);
            if (type < 0) type = ID_JUNK;
            sym = dsymbol_alloc(symbols, rb_cSymbol, str, enc, type);
        }
        else {
            ID id = intern_str(str, 0);
            sym = ID2SYM(id);
        }
    }
    return sym;
}

#length ⇒ Integer Also known as: #size

Returns the count of characters (not bytes) in self:

'foo'.length        # => 3
'тест'.length       # => 4
'こんにちは'.length   # => 5

Contrast with #bytesize:

'foo'.bytesize        # => 3
'тест'.bytesize       # => 8
'こんにちは'.bytesize   # => 15

[ GitHub ]

# File 'string.c', line 2395


VALUE
rb_str_length(VALUE str)
{
    return LONG2NUM(str_strlen(str, NULL));
}

#lines(Line_sep = $/, chomp: false) ⇒ `String`

Forms substrings (“lines”) of self according to the given arguments (see #each_line for details); returns the lines in an array.

[ GitHub ]

# File 'string.c', line 9759


static VALUE
rb_str_lines(int argc, VALUE *argv, VALUE str)
{
    VALUE ary = WANTARRAY("lines", 0);
    return rb_str_enumerate_lines(argc, argv, str, ary);
}

#ljust(size, pad_string = ' ') ⇒ `String`

Returns a left-justified copy of self.

If integer argument #size is greater than the size (in characters) of self, returns a new string of length #size that is a copy of self, left justified and padded on the right with pad_string:

'hello'.ljust(10)       # => "hello     "
'  hello'.ljust(10)     # => "  hello   "
'hello'.ljust(10, 'ab') # => "helloababa"
'тест'.ljust(10)        # => "тест      "
'こんにちは'.ljust(10)    # => "こんにちは     "

If #size is not greater than the size of self, returns a copy of self:

'hello'.ljust(5)  # => "hello"
'hello'.ljust(1)  # => "hello"

Related: #rjust, #center.

[ GitHub ]

# File 'string.c', line 11092


static VALUE
rb_str_ljust(int argc, VALUE *argv, VALUE str)
{
    return rb_str_justify(argc, argv, str, 'l');
}

#lstrip ⇒ `String`

Returns a copy of self with leading whitespace removed; see Whitespace in Strings:

whitespace = "\x00\t\n\v\f\r "
s = whitespace + 'abc' + whitespace
s        # => "\u0000\t\n\v\f\r abc\u0000\t\n\v\f\r "
s.lstrip # => "abc\u0000\t\n\v\f\r "

Related: #rstrip, #strip.

[ GitHub ]

# File 'string.c', line 10422


static VALUE
rb_str_lstrip(VALUE str)
{
    char *start;
    long len, loffset;
    RSTRING_GETMEM(str, start, len);
    loffset = lstrip_offset(str, start, start+len, STR_ENC_GET(str));
    if (loffset <= 0) return str_duplicate(rb_cString, str);
    return rb_str_subseq(str, loffset, len - loffset);
}

#lstrip! ⇒ `self`^?

Like #lstrip, except that any modifications are made in self; returns self if any modification are made, nil otherwise.

Related: #rstrip!, #strip!.

[ GitHub ]

# File 'string.c', line 10384


static VALUE
rb_str_lstrip_bang(VALUE str)
{
    rb_encoding *enc;
    char *start, *s;
    long olen, loffset;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    RSTRING_GETMEM(str, start, olen);
    loffset = lstrip_offset(str, start, start+olen, enc);
    if (loffset > 0) {
        long len = olen-loffset;
        s = start + loffset;
        memmove(start, s, len);
        STR_SET_LEN(str, len);
        TERM_FILL(start+len, rb_enc_mbminlen(enc));
        return str;
    }
    return Qnil;
}

#match(pattern, offset = 0) ⇒ MatchData^? #match(pattern, offset = 0) {|matchdata| ... } ⇒ Object

Returns a ::MatchData object (or nil) based on self and the given pattern.

Note: also updates Regexp@Global+Variables.

Computes regexp by converting pattern (if not already a ::Regexp).
```
regexp = Regexp.new(pattern)
```
Computes matchdata, which will be either a ::MatchData object or nil (see Regexp#match):
```
matchdata = regexp.match(self)
```

With no block given, returns the computed matchdata:

'foo'.match('f') # => #<MatchData "f">
'foo'.match('o') # => #<MatchData "o">
'foo'.match('x') # => nil

If Integer argument offset is given, the search begins at index offset:

'foo'.match('f', 1) # => nil
'foo'.match('o', 1) # => #<MatchData "o">

With a block given, calls the block with the computed matchdata and returns the block’s return value:

'foo'.match(/o/) {|matchdata| matchdata } # => #<MatchData "o">
'foo'.match(/x/) {|matchdata| matchdata } # => nil
'foo'.match(/f/, 1) {|matchdata| matchdata } # => nil

[ GitHub ]

# File 'string.c', line 5124


static VALUE
rb_str_match_m(int argc, VALUE *argv, VALUE str)
{
    VALUE re, result;
    if (argc < 1)
        rb_check_arity(argc, 1, 2);
    re = argv[0];
    argv[0] = str;
    result = rb_funcallv(get_pat(re), rb_intern("match"), argc, argv);
    if (!NIL_P(result) && rb_block_given_p()) {
        return rb_yield(result);
    }
    return result;
}

#match?(pattern, offset = 0) ⇒ `Boolean`

Returns true or false based on whether a match is found for self and pattern.

Note: does not update Regexp@Global+Variables.

Computes regexp by converting pattern (if not already a ::Regexp).

regexp = Regexp.new(pattern)

Returns true if self.match(regexp)</tt> returns a ::MatchData object, false otherwise:

'foo'.match?(/o/) # => true
'foo'.match?('o') # => true
'foo'.match?(/x/) # => false

If Integer argument offset is given, the search begins at index offset:

'foo'.match?('f', 1) # => false
'foo'.match?('o', 1) # => true

[ GitHub ]

# File 'string.c', line 5163


static VALUE
rb_str_match_m_p(int argc, VALUE *argv, VALUE str)
{
    VALUE re;
    rb_check_arity(argc, 1, 2);
    re = get_pat(argv[0]);
    return rb_reg_match_p(re, str, argc > 1 ? NUM2LONG(argv[1]) : 0);
}

#next ⇒ `String` Also known as: #succ

Returns the successor to self. The successor is calculated by incrementing characters.

The first character to be incremented is the rightmost alphanumeric: or, if no alphanumerics, the rightmost character:

'THX1138'.succ # => "THX1139"
'<<koala>>'.succ # => "<<koalb>>"
'***'.succ # => '**+'

The successor to a digit is another digit, “carrying” to the next-left character for a “rollover” from 9 to 0, and prepending another digit if necessary:

'00'.succ # => "01"
'09'.succ # => "10"
'99'.succ # => "100"

The successor to a letter is another letter of the same case, carrying to the next-left character for a rollover, and prepending another same-case letter if necessary:

'aa'.succ # => "ab"
'az'.succ # => "ba"
'zz'.succ # => "aaa"
'AA'.succ # => "AB"
'AZ'.succ # => "BA"
'ZZ'.succ # => "AAA"

The successor to a non-alphanumeric character is the next character in the underlying character set’s collating sequence, carrying to the next-left character for a rollover, and prepending another character if necessary:

s = 0.chr * 3
s # => "\x00\x00\x00"
s.succ # => "\x00\x00\x01"
s = 255.chr * 3
s # => "\xFF\xFF\xFF"
s.succ # => "\x01\x00\x00\x00"

Carrying can occur between and among mixtures of alphanumeric characters:

s = 'zz99zz99'
s.succ # => "aaa00aa00"
s = '99zz99zz'
s.succ # => "100aa00aa"

The successor to an empty String is a new empty String:

''.succ # => ""

[ GitHub ]

# File 'string.c', line 5415


VALUE
rb_str_succ(VALUE orig)
{
    VALUE str;
    str = rb_str_new(RSTRING_PTR(orig), RSTRING_LEN(orig));
    rb_enc_cr_str_copy_for_substr(str, orig);
    return str_succ(str);
}

#next! ⇒ `self` Also known as: #succ!

Equivalent to #succ, but modifies self in place; returns self.

[ GitHub ]

# File 'string.c', line 5519


static VALUE
rb_str_succ_bang(VALUE str)
{
    rb_str_modify(str);
    str_succ(str);
    return str;
}

#oct ⇒ Integer

Interprets the leading substring of self as a string of octal digits (with an optional sign) and returns the corresponding number; returns zero if there is no such leading substring:

'123'.oct             # => 83
'-377'.oct            # => -255
'0377non-numeric'.oct # => 255
'non-numeric'.oct     # => 0

If self starts with 0, radix indicators are honored; see Kernel.Integer.

Related: #hex.

[ GitHub ]

# File 'string.c', line 10767


static VALUE
rb_str_oct(VALUE str)
{
    return rb_str_to_inum(str, -8, FALSE);
}

#ord ⇒ Integer

Returns the integer ordinal of the first character of self:

'h'.ord         # => 104
'hello'.ord     # => 104
'тест'.ord      # => 1090
'こんにちは'.ord  # => 12371

[ GitHub ]

# File 'string.c', line 10920


static VALUE
rb_str_ord(VALUE s)
{
    unsigned int c;

    c = rb_enc_codepoint(RSTRING_PTR(s), RSTRING_END(s), STR_ENC_GET(s));
    return UINT2NUM(c);
}

#partition(string_or_regexp) ⇒ Array, ...

Returns a 3-element array of substrings of self.

Matches a pattern against self, scanning from the beginning. The pattern is:

string_or_regexp itself, if it is a ::Regexp.
Regexp.quote(string_or_regexp), if string_or_regexp is a string.

If the pattern is matched, returns pre-match, first-match, post-match:

'hello'.partition('l')      # => ["he", "l", "lo"]
'hello'.partition('ll')     # => ["he", "ll", "o"]
'hello'.partition('h')      # => ["", "h", "ello"]
'hello'.partition('o')      # => ["hell", "o", ""]
'hello'.partition(/l+/)     #=> ["he", "ll", "o"]
'hello'.partition('')       # => ["", "", "hello"]
'тест'.partition('т')       # => ["", "т", "ест"]
'こんにちは'.partition('に')  # => ["こん", "に", "ちは"]

If the pattern is not matched, returns a copy of self and two empty strings:

'hello'.partition('x') # => ["hello", "", ""]

Related: #rpartition, #split.

[ GitHub ]

# File 'string.c', line 11139


static VALUE
rb_str_partition(VALUE str, VALUE sep)
{
    long pos;

    sep = get_pat_quoted(sep, 0);
    if (RB_TYPE_P(sep, T_REGEXP)) {
        if (rb_reg_search(sep, str, 0, 0) < 0) {
            goto failed;
        }
        VALUE match = rb_backref_get();
        struct re_registers *regs = RMATCH_REGS(match);

        pos = BEG(0);
        sep = rb_str_subseq(str, pos, END(0) - pos);
    }
    else {
        pos = rb_str_index(str, sep, 0);
        if (pos < 0) goto failed;
    }
    return rb_ary_new3(3, rb_str_subseq(str, 0, pos),
                          sep,
                          rb_str_subseq(str, pos+RSTRING_LEN(sep),
                                             RSTRING_LEN(str)-pos-RSTRING_LEN(sep)));

  failed:
    return rb_ary_new3(3, str_duplicate(rb_cString, str), str_new_empty_String(str), str_new_empty_String(str));
}

#prepend(*other_strings) ⇒ `String`

Prepends each string in other_strings to self and returns self:

s = 'foo'
s.prepend('bar', 'baz') # => "barbazfoo"
s                       # => "barbazfoo"

Related: #concat.

[ GitHub ]

# File 'string.c', line 4095


static VALUE
rb_str_prepend_multi(int argc, VALUE *argv, VALUE str)
{
    str_modifiable(str);

    if (argc == 1) {
        rb_str_update(str, 0L, 0L, argv[0]);
    }
    else if (argc > 1) {
        int i;
        VALUE arg_str = rb_str_tmp_new(0);
        rb_enc_copy(arg_str, str);
        for (i = 0; i < argc; i++) {
            rb_str_append(arg_str, argv[i]);
        }
        rb_str_update(str, 0L, 0L, arg_str);
    }

    return str;
}

#replace(other_string) ⇒ `self` Also known as: #initialize_copy

Replaces the contents of self with the contents of other_string:

s = 'foo'        # => "foo"
s.replace('bar') # => "bar"

[ GitHub ]

# File 'string.c', line 6653


VALUE
rb_str_replace(VALUE str, VALUE str2)
{
    str_modifiable(str);
    if (str == str2) return str;

    StringValue(str2);
    str_discard(str);
    return str_replace(str, str2);
}

#reverse ⇒ `String`

Returns a new string with the characters from self in reverse order.

'stressed'.reverse # => "desserts"

[ GitHub ]

# File 'string.c', line 6996


static VALUE
rb_str_reverse(VALUE str)
{
    rb_encoding *enc;
    VALUE rev;
    char *s, *e, *p;
    int cr;

    if (RSTRING_LEN(str) <= 1) return str_duplicate(rb_cString, str);
    enc = STR_ENC_GET(str);
    rev = rb_str_new(0, RSTRING_LEN(str));
    s = RSTRING_PTR(str); e = RSTRING_END(str);
    p = RSTRING_END(rev);
    cr = ENC_CODERANGE(str);

    if (RSTRING_LEN(str) > 1) {
        if (single_byte_optimizable(str)) {
            while (s < e) {
                *--p = *s++;
            }
        }
        else if (cr == ENC_CODERANGE_VALID) {
            while (s < e) {
                int clen = rb_enc_fast_mbclen(s, e, enc);

                p -= clen;
                memcpy(p, s, clen);
                s += clen;
            }
        }
        else {
            cr = rb_enc_asciicompat(enc) ?
                ENC_CODERANGE_7BIT : ENC_CODERANGE_VALID;
            while (s < e) {
                int clen = rb_enc_mbclen(s, e, enc);

                if (clen > 1 || (*s & 0x80)) cr = ENC_CODERANGE_UNKNOWN;
                p -= clen;
                memcpy(p, s, clen);
                s += clen;
            }
        }
    }
    STR_SET_LEN(rev, RSTRING_LEN(str));
    str_enc_copy_direct(rev, str);
    ENC_CODERANGE_SET(rev, cr);

    return rev;
}

#reverse! ⇒ `self`

Returns self with its characters reversed:

s = 'stressed'
s.reverse! # => "desserts"
s          # => "desserts"

[ GitHub ]

# File 'string.c', line 7059


static VALUE
rb_str_reverse_bang(VALUE str)
{
    if (RSTRING_LEN(str) > 1) {
        if (single_byte_optimizable(str)) {
            char *s, *e, c;

            str_modify_keep_cr(str);
            s = RSTRING_PTR(str);
            e = RSTRING_END(str) - 1;
            while (s < e) {
                c = *s;
                *s++ = *e;
                *e-- = c;
            }
        }
        else {
            str_shared_replace(str, rb_str_reverse(str));
        }
    }
    else {
        str_modify_keep_cr(str);
    }
    return str;
}

#rindex(substring, offset = self.length) ⇒ Integer^? #rindex(regexp, offset = self.length) ⇒ Integer^?

Returns the ::Integer index of the last occurrence of the given substring, or nil if none found:

'foo'.rindex('f') # => 0
'foo'.rindex('o') # => 2
'foo'.rindex('oo') # => 1
'foo'.rindex('ooo') # => nil

Returns the ::Integer index of the last match for the given ::Regexp regexp, or nil if none found:

'foo'.rindex(/f/) # => 0
'foo'.rindex(/o/) # => 2
'foo'.rindex(/oo/) # => 1
'foo'.rindex(/ooo/) # => nil

The last match means starting at the possible last position, not the last of longest matches.

'foo'.rindex(/o+/) # => 2
$~ #=> #<MatchData "o">

To get the last longest match, needs to combine with negative lookbehind.

'foo'.rindex(/(?<!o)o+/) # => 1
$~ #=> #<MatchData "oo">

Or #index with negative lookforward.

'foo'.index(/o+(?!.*o)/) # => 1
$~ #=> #<MatchData "oo">

::Integer argument offset, if given and non-negative, specifies the maximum starting position in the string to end the search:

'foo'.rindex('o', 0) # => nil
'foo'.rindex('o', 1) # => 1
'foo'.rindex('o', 2) # => 2
'foo'.rindex('o', 3) # => 2

If offset is a negative ::Integer, the maximum starting position in the string to end the search is the sum of the string’s length and offset:

'foo'.rindex('o', -1) # => 2
'foo'.rindex('o', -2) # => 1
'foo'.rindex('o', -3) # => nil
'foo'.rindex('o', -4) # => nil

Related: #index.

[ GitHub ]

# File 'string.c', line 4839


static VALUE
rb_str_rindex_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE initpos;
    rb_encoding *enc = STR_ENC_GET(str);
    long pos, len = str_strlen(str, enc); /* str's enc */

    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
        pos = NUM2LONG(initpos);
        if (pos < 0 && (pos += len) < 0) {
            if (RB_TYPE_P(sub, T_REGEXP)) {
                rb_backref_set(Qnil);
            }
            return Qnil;
        }
        if (pos > len) pos = len;
    }
    else {
        pos = len;
    }

    if (RB_TYPE_P(sub, T_REGEXP)) {
        /* enc = rb_enc_check(str, sub); */
        pos = str_offset(RSTRING_PTR(str), RSTRING_END(str), pos,
                         enc, single_byte_optimizable(str));

        if (rb_reg_search(sub, str, pos, 1) >= 0) {
            VALUE match = rb_backref_get();
            struct re_registers *regs = RMATCH_REGS(match);
            pos = rb_str_sublen(str, BEG(0));
            return LONG2NUM(pos);
        }
    }
    else {
        StringValue(sub);
        pos = rb_str_rindex(str, sub, pos);
        if (pos >= 0) {
            pos = rb_str_sublen(str, pos);
            return LONG2NUM(pos);
        }
    }
    return Qnil;
}

#rjust(size, pad_string = ' ') ⇒ `String`

Returns a right-justified copy of self.

If integer argument #size is greater than the size (in characters) of self, returns a new string of length #size that is a copy of self, right justified and padded on the left with pad_string:

'hello'.rjust(10)       # => "     hello"
'hello  '.rjust(10)     # => "   hello  "
'hello'.rjust(10, 'ab') # => "ababahello"
'тест'.rjust(10)        # => "      тест"
'こんにちは'.rjust(10)    # => "     こんにちは"

If #size is not greater than the size of self, returns a copy of self:

'hello'.rjust(5, 'ab')  # => "hello"
'hello'.rjust(1, 'ab')  # => "hello"

Related: #ljust, #center.

[ GitHub ]

# File 'string.c', line 11108


static VALUE
rb_str_rjust(int argc, VALUE *argv, VALUE str)
{
    return rb_str_justify(argc, argv, str, 'r');
}

#rpartition(sep) ⇒ Array, ...

Returns a 3-element array of substrings of self.

Matches a pattern against self, scanning backwards from the end. The pattern is:

string_or_regexp itself, if it is a ::Regexp.
Regexp.quote(string_or_regexp), if string_or_regexp is a string.

If the pattern is matched, returns pre-match, last-match, post-match:

'hello'.rpartition('l')      # => ["hel", "l", "o"]
'hello'.rpartition('ll')     # => ["he", "ll", "o"]
'hello'.rpartition('h')      # => ["", "h", "ello"]
'hello'.rpartition('o')      # => ["hell", "o", ""]
'hello'.rpartition(/l+/)     # => ["hel", "l", "o"]
'hello'.rpartition('')       # => ["hello", "", ""]
'тест'.rpartition('т')       # => ["тес", "т", ""]
'こんにちは'.rpartition('に')  # => ["こん", "に", "ちは"]

If the pattern is not matched, returns two empty strings and a copy of self:

'hello'.rpartition('x') # => ["", "", "hello"]

Related: #partition, #split.

[ GitHub ]

# File 'string.c', line 11176


static VALUE
rb_str_rpartition(VALUE str, VALUE sep)
{
    long pos = RSTRING_LEN(str);

    sep = get_pat_quoted(sep, 0);
    if (RB_TYPE_P(sep, T_REGEXP)) {
        if (rb_reg_search(sep, str, pos, 1) < 0) {
            goto failed;
        }
        VALUE match = rb_backref_get();
        struct re_registers *regs = RMATCH_REGS(match);

        pos = BEG(0);
        sep = rb_str_subseq(str, pos, END(0) - pos);
    }
    else {
        pos = rb_str_sublen(str, pos);
        pos = rb_str_rindex(str, sep, pos);
        if (pos < 0) {
            goto failed;
        }
    }

    return rb_ary_new3(3, rb_str_subseq(str, 0, pos),
                          sep,
                          rb_str_subseq(str, pos+RSTRING_LEN(sep),
                                        RSTRING_LEN(str)-pos-RSTRING_LEN(sep)));
  failed:
    return rb_ary_new3(3, str_new_empty_String(str), str_new_empty_String(str), str_duplicate(rb_cString, str));
}

#rstrip ⇒ `String`

Returns a copy of the receiver with trailing whitespace removed; see Whitespace in Strings:

whitespace = "\x00\t\n\v\f\r "
s = whitespace + 'abc' + whitespace
s        # => "\u0000\t\n\v\f\r abc\u0000\t\n\v\f\r "
s.rstrip # => "\u0000\t\n\v\f\r abc"

Related: #lstrip, #strip.

[ GitHub ]

# File 'string.c', line 10509


static VALUE
rb_str_rstrip(VALUE str)
{
    rb_encoding *enc;
    char *start;
    long olen, roffset;

    enc = STR_ENC_GET(str);
    RSTRING_GETMEM(str, start, olen);
    roffset = rstrip_offset(str, start, start+olen, enc);

    if (roffset <= 0) return str_duplicate(rb_cString, str);
    return rb_str_subseq(str, 0, olen-roffset);
}

#rstrip! ⇒ `self`^?

Like #rstrip, except that any modifications are made in self; returns self if any modification are made, nil otherwise.

Related: #lstrip!, #strip!.

[ GitHub ]

# File 'string.c', line 10472


static VALUE
rb_str_rstrip_bang(VALUE str)
{
    rb_encoding *enc;
    char *start;
    long olen, roffset;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    RSTRING_GETMEM(str, start, olen);
    roffset = rstrip_offset(str, start, start+olen, enc);
    if (roffset > 0) {
        long len = olen - roffset;

        STR_SET_LEN(str, len);
        TERM_FILL(start+len, rb_enc_mbminlen(enc));
        return str;
    }
    return Qnil;
}

#scan(string_or_regexp) ⇒ Array #scan(string_or_regexp) {|matches| ... } ⇒ `self`

Matches a pattern against self; the pattern is:

string_or_regexp itself, if it is a ::Regexp.
Regexp.quote(string_or_regexp), if string_or_regexp is a string.

Iterates through self, generating a collection of matching results:

If the pattern contains no groups, each result is the matched string, $&.
If the pattern contains groups, each result is an array containing one entry per group.

With no block given, returns an array of the results:

s = 'cruel world'
s.scan(/\w+/)      # => ["cruel", "world"]
s.scan(/.../)      # => ["cru", "el ", "wor"]
s.scan(/(...)/)    # => [["cru"], ["el "], ["wor"]]
s.scan(/(..)(..)/) # => [["cr", "ue"], ["l ", "wo"]]

With a block given, calls the block with each result; returns self:

s.scan(/\w+/) {|w| print "<<#{w}>> " }
print "\n"
s.scan(/(.)(.)/) {|x,y| print y, x }
print "\n"

Output:

<<cruel>> <<world>>
rceu lowlr

[ GitHub ]

# File 'string.c', line 10688


static VALUE
rb_str_scan(VALUE str, VALUE pat)
{
    VALUE result;
    long start = 0;
    long last = -1, prev = 0;
    char *p = RSTRING_PTR(str); long len = RSTRING_LEN(str);

    pat = get_pat_quoted(pat, 1);
    mustnot_broken(str);
    if (!rb_block_given_p()) {
        VALUE ary = rb_ary_new();

        while (!NIL_P(result = scan_once(str, pat, &start, 0))) {
            last = prev;
            prev = start;
            rb_ary_push(ary, result);
        }
        if (last >= 0) rb_pat_search(pat, str, last, 1);
        else rb_backref_set(Qnil);
        return ary;
    }

    while (!NIL_P(result = scan_once(str, pat, &start, 1))) {
        last = prev;
        prev = start;
        rb_yield(result);
        str_mod_check(str, p, len);
    }
    if (last >= 0) rb_pat_search(pat, str, last, 1);
    return str;
}

#scrub(replacement_string = default_replacement) ⇒ `String` #scrub {|bytes| ... } ⇒ `String`

Returns a copy of self with each invalid byte sequence replaced by the given replacement_string.

With no block given and no argument, replaces each invalid sequence with the default replacement string ("�" for a Unicode encoding, '?' otherwise):

s = "foo\x81\x81bar"
s.scrub # => "foo��bar"

With no block given and argument replacement_string given, replaces each invalid sequence with that string:

"foo\x81\x81bar".scrub('xyzzy') # => "fooxyzzyxyzzybar"

With a block given, replaces each invalid sequence with the value of the block:

"foo\x81\x81bar".scrub {|bytes| p bytes; 'XYZZY' }
# => "fooXYZZYXYZZYbar"

Output:

"\x81"
"\x81"

[ GitHub ]

# File 'string.c', line 11919


static VALUE
str_scrub(int argc, VALUE *argv, VALUE str)
{
    VALUE repl = argc ? (rb_check_arity(argc, 0, 1), argv[0]) : Qnil;
    VALUE new = rb_str_scrub(str, repl);
    return NIL_P(new) ? str_duplicate(rb_cString, str): new;
}

#scrub! ⇒ `self` #scrub!(replacement_string = default_replacement) ⇒ `self` #scrub! {|bytes| ... } ⇒ `self`

Like #scrub, except that any replacements are made in self.

[ GitHub ]

# File 'string.c', line 11936


static VALUE
str_scrub_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE repl = argc ? (rb_check_arity(argc, 0, 1), argv[0]) : Qnil;
    VALUE new = rb_str_scrub(str, repl);
    if (!NIL_P(new)) rb_str_replace(str, new);
    return str;
}

#setbyte(index, integer) ⇒ Integer

Sets the byte at zero-based #index to integer; returns integer:

s = 'abcde'      # => "abcde"
s.setbyte(0, 98) # => 98
s                # => "bbcde"

Related: #getbyte.

[ GitHub ]

# File 'string.c', line 6744


VALUE
rb_str_setbyte(VALUE str, VALUE index, VALUE value)
{
    long pos = NUM2LONG(index);
    long len = RSTRING_LEN(str);
    char *ptr, *head, *left = 0;
    rb_encoding *enc;
    int cr = ENC_CODERANGE_UNKNOWN, width, nlen;

    if (pos < -len || len <= pos)
        rb_raise(rb_eIndexError, "index %ld out of string", pos);
    if (pos < 0)
        pos += len;

    VALUE v = rb_to_int(value);
    VALUE w = rb_int_and(v, INT2FIX(0xff));
    char byte = (char)(NUM2INT(w) & 0xFF);

    if (!str_independent(str))
        str_make_independent(str);
    enc = STR_ENC_GET(str);
    head = RSTRING_PTR(str);
    ptr = &head[pos];
    if (!STR_EMBED_P(str)) {
        cr = ENC_CODERANGE(str);
        switch (cr) {
          case ENC_CODERANGE_7BIT:
            left = ptr;
            *ptr = byte;
            if (ISASCII(byte)) goto end;
            nlen = rb_enc_precise_mbclen(left, head+len, enc);
            if (!MBCLEN_CHARFOUND_P(nlen))
                ENC_CODERANGE_SET(str, ENC_CODERANGE_BROKEN);
            else
                ENC_CODERANGE_SET(str, ENC_CODERANGE_VALID);
            goto end;
          case ENC_CODERANGE_VALID:
            left = rb_enc_left_char_head(head, ptr, head+len, enc);
            width = rb_enc_precise_mbclen(left, head+len, enc);
            *ptr = byte;
            nlen = rb_enc_precise_mbclen(left, head+len, enc);
            if (!MBCLEN_CHARFOUND_P(nlen))
                ENC_CODERANGE_SET(str, ENC_CODERANGE_BROKEN);
            else if (MBCLEN_CHARFOUND_LEN(nlen) != width || ISASCII(byte))
                ENC_CODERANGE_CLEAR(str);
            goto end;
        }
    }
    ENC_CODERANGE_CLEAR(str);
    *ptr = byte;

  end:
    return value;
}

#length ⇒ Integer #size ⇒ Integer

Alias for #length.

#[](index) ⇒ `String`^? #[](start, length) ⇒ `String`^? #[](range) ⇒ `String`^? #[](substring) ⇒ `String`^?

Alias for #[].

#slice!(index) ⇒ `String`^? #slice!(start, length) ⇒ `String`^? #slice!(range) ⇒ `String`^? #slice!(regexp, capture = 0) ⇒ `String`^? #slice!(substring) ⇒ `String`^?

Removes and returns the substring of self specified by the arguments. See String Slices.

A few examples:

string = "This is a string"
string.slice!(2)        #=> "i"
string.slice!(3..6)     #=> " is "
string.slice!(/s.*t/)   #=> "sa st"
string.slice!("r")      #=> "r"
string                  #=> "Thing"

[ GitHub ]

# File 'string.c', line 6137


static VALUE
rb_str_slice_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE result = Qnil;
    VALUE indx;
    long beg, len = 1;
    char *p;

    rb_check_arity(argc, 1, 2);
    str_modify_keep_cr(str);
    indx = argv[0];
    if (RB_TYPE_P(indx, T_REGEXP)) {
        if (rb_reg_search(indx, str, 0, 0) < 0) return Qnil;
        VALUE match = rb_backref_get();
        struct re_registers *regs = RMATCH_REGS(match);
        int nth = 0;
        if (argc > 1 && (nth = rb_reg_backref_number(match, argv[1])) < 0) {
            if ((nth += regs->num_regs) <= 0) return Qnil;
        }
        else if (nth >= regs->num_regs) return Qnil;
        beg = BEG(nth);
        len = END(nth) - beg;
        goto subseq;
    }
    else if (argc == 2) {
        beg = NUM2LONG(indx);
        len = NUM2LONG(argv[1]);
        goto num_index;
    }
    else if (FIXNUM_P(indx)) {
        beg = FIX2LONG(indx);
        if (!(p = rb_str_subpos(str, beg, &len))) return Qnil;
        if (!len) return Qnil;
        beg = p - RSTRING_PTR(str);
        goto subseq;
    }
    else if (RB_TYPE_P(indx, T_STRING)) {
        beg = rb_str_index(str, indx, 0);
        if (beg == -1) return Qnil;
        len = RSTRING_LEN(indx);
        result = str_duplicate(rb_cString, indx);
        goto squash;
    }
    else {
        switch (rb_range_beg_len(indx, &beg, &len, str_strlen(str, NULL), 0)) {
          case Qnil:
            return Qnil;
          case Qfalse:
            beg = NUM2LONG(indx);
            if (!(p = rb_str_subpos(str, beg, &len))) return Qnil;
            if (!len) return Qnil;
            beg = p - RSTRING_PTR(str);
            goto subseq;
          default:
            goto num_index;
        }
    }

  num_index:
    if (!(p = rb_str_subpos(str, beg, &len))) return Qnil;
    beg = p - RSTRING_PTR(str);

  subseq:
    result = rb_str_new(RSTRING_PTR(str)+beg, len);
    rb_enc_cr_str_copy_for_substr(result, str);

  squash:
    if (len > 0) {
        if (beg == 0) {
            rb_str_drop_bytes(str, len);
        }
        else {
            char *sptr = RSTRING_PTR(str);
            long slen = RSTRING_LEN(str);
            if (beg + len > slen) /* pathological check */
                len = slen - beg;
            memmove(sptr + beg,
                    sptr + beg + len,
                    slen - (beg + len));
            slen -= len;
            STR_SET_LEN(str, slen);
            TERM_FILL(&sptr[slen], TERM_LEN(str));
        }
    }
    return result;
}

#split(field_sep = $;, limit = 0) ⇒ Array #split(field_sep = $;, limit = 0) {|substring| ... } ⇒ `self`

Returns an array of substrings of self that are the result of splitting self at each occurrence of the given field separator field_sep.

When field_sep is $;:

If $; is nil (its default value), the split occurs just as if field_sep were given as a space character (see below).
If $; is a string, the split occurs just as if field_sep were given as that string (see below).

When field_sep is ' ' and limit is 0 (its default value), the split occurs at each sequence of whitespace:

'abc def ghi'.split(' ')          # => ["abc", "def", "ghi"]
"abc \n\tdef\t\n  ghi".split(' ') # => ["abc", "def", "ghi"]
'abc  def   ghi'.split(' ')       # => ["abc", "def", "ghi"]
''.split(' ')                     # => []

When field_sep is a string different from ' ' and limit is 0, the split occurs at each occurrence of field_sep; trailing empty substrings are not returned:

'abracadabra'.split('ab')   # => ["", "racad", "ra"]
'aaabcdaaa'.split('a')      # => ["", "", "", "bcd"]
''.split('a')               # => []
'3.14159'.split('1')        # => ["3.", "4", "59"]
'!@#$%^$&*($)_+'.split('$') # => ["!@#", "%^", "&*(", ")_+"]
'тест'.split('т')           # => ["", "ес"]
'こんにちは'.split('に')      # => ["こん", "ちは"]

When field_sep is a ::Regexp and limit is 0, the split occurs at each occurrence of a match; trailing empty substrings are not returned:

'abracadabra'.split(/ab/) # => ["", "racad", "ra"]
'aaabcdaaa'.split(/a/)    # => ["", "", "", "bcd"]
'aaabcdaaa'.split(//)     # => ["a", "a", "a", "b", "c", "d", "a", "a", "a"]
'1 + 1 == 2'.split(/\W+/) # => ["1", "1", "2"]

If the Regexp contains groups, their matches are also included in the returned array:

'1:2:3'.split(/(:)()()/, 2) # => ["1", ":", "", "", "2:3"]

As seen above, if limit is 0, trailing empty substrings are not returned:

'aaabcdaaa'.split('a')    # => ["", "", "", "bcd"]

If limit is positive integer n, no more than n - 1- splits occur, so that at most n substrings are returned, and trailing empty substrings are included:

'aaabcdaaa'.split('a', 1) # => ["aaabcdaaa"]
'aaabcdaaa'.split('a', 2) # => ["", "aabcdaaa"]
'aaabcdaaa'.split('a', 5) # => ["", "", "", "bcd", "aa"]
'aaabcdaaa'.split('a', 7) # => ["", "", "", "bcd", "", "", ""]
'aaabcdaaa'.split('a', 8) # => ["", "", "", "bcd", "", "", ""]

Note that if field_sep is a Regexp containing groups, their matches are in the returned array, but do not count toward the limit.

If limit is negative, it behaves the same as if limit was zero, meaning that there is no limit, and trailing empty substrings are included:

'aaabcdaaa'.split('a', -1) # => ["", "", "", "bcd", "", "", ""]

If a block is given, it is called with each substring and returns self:

'abc def ghi'.split(' ') {|substring| p substring }

Output:

"abc"
"def"
"ghi"
#=> "abc def ghi"

Note that the above example is functionally the same as calling #each after #split and giving the same block. However, the above example has better performance because it avoids the creation of an intermediate array. Also, note the different return values.

'abc def ghi'.split(' ').each {|substring| p substring }

Output:

"abc"
"def"
"ghi"
#=> ["abc", "def", "ghi"]

Related: #partition, #rpartition.

[ GitHub ]

# File 'string.c', line 9314


static VALUE
rb_str_split_m(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    VALUE spat;
    VALUE limit;
    split_type_t split_type;
    long beg, end, i = 0, empty_count = -1;
    int lim = 0;
    VALUE result, tmp;

    result = rb_block_given_p() ? Qfalse : Qnil;
    if (rb_scan_args(argc, argv, "02", &spat, &limit) == 2) {
        lim = NUM2INT(limit);
        if (lim <= 0) limit = Qnil;
        else if (lim == 1) {
            if (RSTRING_LEN(str) == 0)
                return result ? rb_ary_new2(0) : str;
            tmp = str_duplicate(rb_cString, str);
            if (!result) {
                rb_yield(tmp);
                return str;
            }
            return rb_ary_new3(1, tmp);
        }
        i = 1;
    }
    if (NIL_P(limit) && !lim) empty_count = 0;

    enc = STR_ENC_GET(str);
    split_type = SPLIT_TYPE_REGEXP;
    if (!NIL_P(spat)) {
        spat = get_pat_quoted(spat, 0);
    }
    else if (NIL_P(spat = rb_fs)) {
        split_type = SPLIT_TYPE_AWK;
    }
    else if (!(spat = rb_fs_check(spat))) {
        rb_raise(rb_eTypeError, "value of $; must be String or Regexp");
    }
    else {
        rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$; is set to non-nil value");
    }
    if (split_type != SPLIT_TYPE_AWK) {
        switch (BUILTIN_TYPE(spat)) {
          case T_REGEXP:
            rb_reg_options(spat); /* check if uninitialized */
            tmp = RREGEXP_SRC(spat);
            split_type = literal_split_pattern(tmp, SPLIT_TYPE_REGEXP);
            if (split_type == SPLIT_TYPE_AWK) {
                spat = tmp;
                split_type = SPLIT_TYPE_STRING;
            }
            break;

          case T_STRING:
            mustnot_broken(spat);
            split_type = literal_split_pattern(spat, SPLIT_TYPE_STRING);
            break;

          default:
            UNREACHABLE_RETURN(Qnil);
        }
    }

#define SPLIT_STR(beg, len) ( \
        empty_count = split_string(result, str, beg, len, empty_count), \
        str_mod_check(str, str_start, str_len))

    beg = 0;
    char *ptr = RSTRING_PTR(str);
    char *const str_start = ptr;
    const long str_len = RSTRING_LEN(str);
    char *const eptr = str_start + str_len;
    if (split_type == SPLIT_TYPE_AWK) {
        char *bptr = ptr;
        int skip = 1;
        unsigned int c;

        if (result) result = rb_ary_new();
        end = beg;
        if (is_ascii_string(str)) {
            while (ptr < eptr) {
                c = (unsigned char)*ptr++;
                if (skip) {
                    if (ascii_isspace(c)) {
                        beg = ptr - bptr;
                    }
                    else {
                        end = ptr - bptr;
                        skip = 0;
                        if (!NIL_P(limit) && lim <= i) break;
                    }
                }
                else if (ascii_isspace(c)) {
                    SPLIT_STR(beg, end-beg);
                    skip = 1;
                    beg = ptr - bptr;
                    if (!NIL_P(limit)) ++i;
                }
                else {
                    end = ptr - bptr;
                }
            }
        }
        else {
            while (ptr < eptr) {
                int n;

                c = rb_enc_codepoint_len(ptr, eptr, &n, enc);
                ptr += n;
                if (skip) {
                    if (rb_isspace(c)) {
                        beg = ptr - bptr;
                    }
                    else {
                        end = ptr - bptr;
                        skip = 0;
                        if (!NIL_P(limit) && lim <= i) break;
                    }
                }
                else if (rb_isspace(c)) {
                    SPLIT_STR(beg, end-beg);
                    skip = 1;
                    beg = ptr - bptr;
                    if (!NIL_P(limit)) ++i;
                }
                else {
                    end = ptr - bptr;
                }
            }
        }
    }
    else if (split_type == SPLIT_TYPE_STRING) {
        char *substr_start = ptr;
        char *sptr = RSTRING_PTR(spat);
        long slen = RSTRING_LEN(spat);

        if (result) result = rb_ary_new();
        mustnot_broken(str);
        enc = rb_enc_check(str, spat);
        while (ptr < eptr &&
               (end = rb_memsearch(sptr, slen, ptr, eptr - ptr, enc)) >= 0) {
            /* Check we are at the start of a char */
            char *t = rb_enc_right_char_head(ptr, ptr + end, eptr, enc);
            if (t != ptr + end) {
                ptr = t;
                continue;
            }
            SPLIT_STR(substr_start - str_start, (ptr+end) - substr_start);
            str_mod_check(spat, sptr, slen);
            ptr += end + slen;
            substr_start = ptr;
            if (!NIL_P(limit) && lim <= ++i) break;
        }
        beg = ptr - str_start;
    }
    else if (split_type == SPLIT_TYPE_CHARS) {
        int n;

        if (result) result = rb_ary_new_capa(RSTRING_LEN(str));
        mustnot_broken(str);
        enc = rb_enc_get(str);
        while (ptr < eptr &&
               (n = rb_enc_precise_mbclen(ptr, eptr, enc)) > 0) {
            SPLIT_STR(ptr - str_start, n);
            ptr += n;
            if (!NIL_P(limit) && lim <= ++i) break;
        }
        beg = ptr - str_start;
    }
    else {
        if (result) result = rb_ary_new();
        long len = RSTRING_LEN(str);
        long start = beg;
        long idx;
        int last_null = 0;
        struct re_registers *regs;
        VALUE match = 0;

        for (; rb_reg_search(spat, str, start, 0) >= 0;
             (match ? (rb_match_unbusy(match), rb_backref_set(match)) : (void)0)) {
            match = rb_backref_get();
            if (!result) rb_match_busy(match);
            regs = RMATCH_REGS(match);
            end = BEG(0);
            if (start == end && BEG(0) == END(0)) {
                if (!ptr) {
                    SPLIT_STR(0, 0);
                    break;
                }
                else if (last_null == 1) {
                    SPLIT_STR(beg, rb_enc_fast_mbclen(ptr+beg, eptr, enc));
                    beg = start;
                }
                else {
                    if (start == len)
                        start++;
                    else
                        start += rb_enc_fast_mbclen(ptr+start,eptr,enc);
                    last_null = 1;
                    continue;
                }
            }
            else {
                SPLIT_STR(beg, end-beg);
                beg = start = END(0);
            }
            last_null = 0;

            for (idx=1; idx < regs->num_regs; idx++) {
                if (BEG(idx) == -1) continue;
                SPLIT_STR(BEG(idx), END(idx)-BEG(idx));
            }
            if (!NIL_P(limit) && lim <= ++i) break;
        }
        if (match) rb_match_unbusy(match);
    }
    if (RSTRING_LEN(str) > 0 && (!NIL_P(limit) || RSTRING_LEN(str) > beg || lim < 0)) {
        SPLIT_STR(beg, RSTRING_LEN(str)-beg);
    }

    return result ? result : str;
}

#squeeze(*selectors) ⇒ `String`

Returns a copy of self with characters specified by selectors “squeezed” (see Multiple Character Selectors):

“Squeezed” means that each multiple-character run of a selected character is squeezed down to a single character; with no arguments given, squeezes all characters:

"yellow moon".squeeze                  #=> "yelow mon"
"  now   is  the".squeeze(" ")         #=> " now is the"
"putters shoot balls".squeeze("m-z")   #=> "puters shot balls"

[ GitHub ]

# File 'string.c', line 9074


static VALUE
rb_str_squeeze(int argc, VALUE *argv, VALUE str)
{
    str = str_duplicate(rb_cString, str);
    rb_str_squeeze_bang(argc, argv, str);
    return str;
}

#squeeze!(*selectors) ⇒ `self`^?

Like #squeeze, but modifies self in place. Returns self if any changes were made, nil otherwise.

[ GitHub ]

# File 'string.c', line 8981


static VALUE
rb_str_squeeze_bang(int argc, VALUE *argv, VALUE str)
{
    char squeez[TR_TABLE_SIZE];
    rb_encoding *enc = 0;
    VALUE del = 0, nodel = 0;
    unsigned char *s, *send, *t;
    int i, modify = 0;
    int ascompat, singlebyte = single_byte_optimizable(str);
    unsigned int save;

    if (argc == 0) {
        enc = STR_ENC_GET(str);
    }
    else {
        for (i=0; i<argc; i++) {
            VALUE s = argv[i];

            StringValue(s);
            enc = rb_enc_check(str, s);
            if (singlebyte && !single_byte_optimizable(s))
                singlebyte = 0;
            tr_setup_table(s, squeez, i==0, &del, &nodel, enc);
        }
    }

    str_modify_keep_cr(str);
    s = t = (unsigned char *)RSTRING_PTR(str);
    if (!s || RSTRING_LEN(str) == 0) return Qnil;
    send = (unsigned char *)RSTRING_END(str);
    save = -1;
    ascompat = rb_enc_asciicompat(enc);

    if (singlebyte) {
        while (s < send) {
            unsigned int c = *s++;
            if (c != save || (argc > 0 && !squeez[c])) {
                *t++ = save = c;
            }
        }
    }
    else {
        while (s < send) {
            unsigned int c;
            int clen;

            if (ascompat && (c = *s) < 0x80) {
                if (c != save || (argc > 0 && !squeez[c])) {
                    *t++ = save = c;
                }
                s++;
            }
            else {
                c = rb_enc_codepoint_len((char *)s, (char *)send, &clen, enc);

                if (c != save || (argc > 0 && !tr_find(c, squeez, del, nodel))) {
                    if (t != s) rb_enc_mbcput(c, t, enc);
                    save = c;
                    t += clen;
                }
                s += clen;
            }
        }
    }

    TERM_FILL((char *)t, TERM_LEN(str));
    if ((char *)t - RSTRING_PTR(str) != RSTRING_LEN(str)) {
        STR_SET_LEN(str, (char *)t - RSTRING_PTR(str));
        modify = 1;
    }

    if (modify) return str;
    return Qnil;
}

#start_with?(*string_or_regexp) ⇒ `Boolean`

Returns whether self starts with any of the given string_or_regexp.

Matches patterns against the beginning of self. For each given string_or_regexp, the pattern is:

string_or_regexp itself, if it is a ::Regexp.
Regexp.quote(string_or_regexp), if string_or_regexp is a string.

Returns true if any pattern matches the beginning, false otherwise:

'hello'.start_with?('hell')               # => true
'hello'.start_with?(/H/i)                 # => true
'hello'.start_with?('heaven', 'hell')     # => true
'hello'.start_with?('heaven', 'paradise') # => false
'тест'.start_with?('т')                   # => true
'こんにちは'.start_with?('こ')              # => true

Related: #end_with?.

[ GitHub ]

# File 'string.c', line 11216


static VALUE
rb_str_start_with(int argc, VALUE *argv, VALUE str)
{
    int i;

    for (i=0; i<argc; i++) {
        VALUE tmp = argv[i];
        if (RB_TYPE_P(tmp, T_REGEXP)) {
            if (rb_reg_start_with_p(tmp, str))
                return Qtrue;
        }
        else {
            const char *p, *s, *e;
            long slen, tlen;
            rb_encoding *enc;

            StringValue(tmp);
            enc = rb_enc_check(str, tmp);
            if ((tlen = RSTRING_LEN(tmp)) == 0) return Qtrue;
            if ((slen = RSTRING_LEN(str)) < tlen) continue;
            p = RSTRING_PTR(str);
            e = p + slen;
            s = p + tlen;
            if (!at_char_right_boundary(p, s, e, enc))
                continue;
            if (memcmp(p, RSTRING_PTR(tmp), tlen) == 0)
                return Qtrue;
        }
    }
    return Qfalse;
}

#strip ⇒ `String`

Returns a copy of the receiver with leading and trailing whitespace removed; see Whitespace in Strings:

whitespace = "\x00\t\n\v\f\r "
s = whitespace + 'abc' + whitespace
s       # => "\u0000\t\n\v\f\r abc\u0000\t\n\v\f\r "
s.strip # => "abc"

Related: #lstrip, #rstrip.

[ GitHub ]

# File 'string.c', line 10577


static VALUE
rb_str_strip(VALUE str)
{
    char *start;
    long olen, loffset, roffset;
    rb_encoding *enc = STR_ENC_GET(str);

    RSTRING_GETMEM(str, start, olen);
    loffset = lstrip_offset(str, start, start+olen, enc);
    roffset = rstrip_offset(str, start+loffset, start+olen, enc);

    if (loffset <= 0 && roffset <= 0) return str_duplicate(rb_cString, str);
    return rb_str_subseq(str, loffset, olen-loffset-roffset);
}

#strip! ⇒ `self`^?

Like #strip, except that any modifications are made in self; returns self if any modification are made, nil otherwise.

Related: #lstrip!, strip!.

[ GitHub ]

# File 'string.c', line 10535


static VALUE
rb_str_strip_bang(VALUE str)
{
    char *start;
    long olen, loffset, roffset;
    rb_encoding *enc;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    RSTRING_GETMEM(str, start, olen);
    loffset = lstrip_offset(str, start, start+olen, enc);
    roffset = rstrip_offset(str, start+loffset, start+olen, enc);

    if (loffset > 0 || roffset > 0) {
        long len = olen-roffset;
        if (loffset > 0) {
            len -= loffset;
            memmove(start, start + loffset, len);
        }
        STR_SET_LEN(str, len);
        TERM_FILL(start+len, rb_enc_mbminlen(enc));
        return str;
    }
    return Qnil;
}

#sub(pattern, replacement) ⇒ `String` #sub(pattern) {|match| ... } ⇒ `String`

Returns a copy of self with only the first occurrence (not all occurrences) of the given pattern replaced.

See Substitution Methods.

Related: #sub!, #gsub, #gsub!.

[ GitHub ]

# File 'string.c', line 6442


static VALUE
rb_str_sub(int argc, VALUE *argv, VALUE str)
{
    str = str_duplicate(rb_cString, str);
    rb_str_sub_bang(argc, argv, str);
    return str;
}

#sub!(pattern, replacement) ⇒ `self`^? #sub!(pattern) {|match| ... } ⇒ `self`^?

Replaces the first occurrence (not all occurrences) of the given pattern on self; returns self if a replacement occurred, nil otherwise.

See Substitution Methods.

Related: #sub, #gsub, #gsub!.

[ GitHub ]

# File 'string.c', line 6317


static VALUE
rb_str_sub_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE pat, repl, hash = Qnil;
    int iter = 0;
    long plen;
    int min_arity = rb_block_given_p() ? 1 : 2;
    long beg;

    rb_check_arity(argc, min_arity, 2);
    if (argc == 1) {
        iter = 1;
    }
    else {
        repl = argv[1];
        hash = rb_check_hash_type(argv[1]);
        if (NIL_P(hash)) {
            StringValue(repl);
        }
    }

    pat = get_pat_quoted(argv[0], 1);

    str_modifiable(str);
    beg = rb_pat_search(pat, str, 0, 1);
    if (beg >= 0) {
        rb_encoding *enc;
        int cr = ENC_CODERANGE(str);
        long beg0, end0;
        VALUE match, match0 = Qnil;
        struct re_registers *regs;
        char *p, *rp;
        long len, rlen;

        match = rb_backref_get();
        regs = RMATCH_REGS(match);
        if (RB_TYPE_P(pat, T_STRING)) {
            beg0 = beg;
            end0 = beg0 + RSTRING_LEN(pat);
            match0 = pat;
        }
        else {
            beg0 = BEG(0);
            end0 = END(0);
            if (iter) match0 = rb_reg_nth_match(0, match);
        }

        if (iter || !NIL_P(hash)) {
            p = RSTRING_PTR(str); len = RSTRING_LEN(str);

            if (iter) {
                repl = rb_obj_as_string(rb_yield(match0));
            }
            else {
                repl = rb_hash_aref(hash, rb_str_subseq(str, beg0, end0 - beg0));
                repl = rb_obj_as_string(repl);
            }
            str_mod_check(str, p, len);
            rb_check_frozen(str);
        }
        else {
            repl = rb_reg_regsub(repl, str, regs, RB_TYPE_P(pat, T_STRING) ? Qnil : pat);
        }

        enc = rb_enc_compatible(str, repl);
        if (!enc) {
            rb_encoding *str_enc = STR_ENC_GET(str);
            p = RSTRING_PTR(str); len = RSTRING_LEN(str);
            if (coderange_scan(p, beg0, str_enc) != ENC_CODERANGE_7BIT ||
                coderange_scan(p+end0, len-end0, str_enc) != ENC_CODERANGE_7BIT) {
                rb_raise(rb_eEncCompatError, "incompatible character encodings: %s and %s",
                         rb_enc_inspect_name(str_enc),
                         rb_enc_inspect_name(STR_ENC_GET(repl)));
            }
            enc = STR_ENC_GET(repl);
        }
        rb_str_modify(str);
        rb_enc_associate(str, enc);
        if (ENC_CODERANGE_UNKNOWN < cr && cr < ENC_CODERANGE_BROKEN) {
            int cr2 = ENC_CODERANGE(repl);
            if (cr2 == ENC_CODERANGE_BROKEN ||
                (cr == ENC_CODERANGE_VALID && cr2 == ENC_CODERANGE_7BIT))
                cr = ENC_CODERANGE_UNKNOWN;
            else
                cr = cr2;
        }
        plen = end0 - beg0;
        rlen = RSTRING_LEN(repl);
        len = RSTRING_LEN(str);
        if (rlen > plen) {
            RESIZE_CAPA(str, len + rlen - plen);
        }
        p = RSTRING_PTR(str);
        if (rlen != plen) {
            memmove(p + beg0 + rlen, p + beg0 + plen, len - beg0 - plen);
        }
        rp = RSTRING_PTR(repl);
        memmove(p + beg0, rp, rlen);
        len += rlen - plen;
        STR_SET_LEN(str, len);
        TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str));
        ENC_CODERANGE_SET(str, cr);

        RB_GC_GUARD(match);

        return str;
    }
    return Qnil;
}

#next ⇒ `String` #succ ⇒ `String`

Alias for #next.

#next! ⇒ `self` #succ! ⇒ `self`

Alias for #next!.

#sum(n = 16) ⇒ Integer

Returns a basic n-bit checksum of the characters in self; the checksum is the sum of the binary value of each byte in self, modulo 2**n - 1:

'hello'.sum     # => 532
'hello'.sum(4)  # => 4
'hello'.sum(64) # => 532
'тест'.sum      # => 1405
'こんにちは'.sum  # => 2582

This is not a particularly strong checksum.

[ GitHub ]

# File 'string.c', line 10936


static VALUE
rb_str_sum(int argc, VALUE *argv, VALUE str)
{
    int bits = 16;
    char *ptr, *p, *pend;
    long len;
    VALUE sum = INT2FIX(0);
    unsigned long sum0 = 0;

    if (rb_check_arity(argc, 0, 1) && (bits = NUM2INT(argv[0])) < 0) {
        bits = 0;
    }
    ptr = p = RSTRING_PTR(str);
    len = RSTRING_LEN(str);
    pend = p + len;

    while (p < pend) {
        if (FIXNUM_MAX - UCHAR_MAX < sum0) {
            sum = rb_funcall(sum, '+', 1, LONG2FIX(sum0));
            str_mod_check(str, ptr, len);
            sum0 = 0;
        }
        sum0 += (unsigned char)*p;
        p++;
    }

    if (bits == 0) {
        if (sum0) {
            sum = rb_funcall(sum, '+', 1, LONG2FIX(sum0));
        }
    }
    else {
        if (sum == INT2FIX(0)) {
            if (bits < (int)sizeof(long)*CHAR_BIT) {
                sum0 &= (((unsigned long)1)<<bits)-1;
            }
            sum = LONG2FIX(sum0);
        }
        else {
            VALUE mod;

            if (sum0) {
                sum = rb_funcall(sum, '+', 1, LONG2FIX(sum0));
            }

            mod = rb_funcall(INT2FIX(1), idLTLT, 1, INT2FIX(bits));
            mod = rb_funcall(mod, '-', 1, INT2FIX(1));
            sum = rb_funcall(sum, '&', 1, mod);
        }
    }
    return sum;
}

#swapcase(mapping) ⇒ `String`

Returns a string containing the characters in self, with cases reversed; each uppercase character is downcased; each lowercase character is upcased:

s = 'Hello World!' # => "Hello World!"
s.swapcase         # => "hELLO wORLD!"

The casing may be affected by the given mapping; see Case Mapping.

Related: #swapcase!.

[ GitHub ]

# File 'string.c', line 8380


static VALUE
rb_str_swapcase(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_DOWNCASE;
    VALUE ret;

    flags = check_case_options(argc, argv, flags);
    enc = str_true_enc(str);
    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return str_duplicate(rb_cString, str);
    if (flags&ONIGENC_CASE_ASCII_ONLY) {
        ret = rb_str_new(0, RSTRING_LEN(str));
        rb_str_ascii_casemap(str, ret, &flags, enc);
    }
    else {
        ret = rb_str_casemap(str, &flags, enc);
    }
    return ret;
}

#swapcase!(mapping) ⇒ `self`^?

Upcases each lowercase character in self; downcases uppercase character; returns self if any changes were made, nil otherwise:

s = 'Hello World!' # => "Hello World!"
s.swapcase!        # => "hELLO wORLD!"
s                  # => "hELLO wORLD!"
''.swapcase!       # => nil

The casing may be affected by the given mapping; see Case Mapping.

Related: #swapcase.

[ GitHub ]

# File 'string.c', line 8343


static VALUE
rb_str_swapcase_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_DOWNCASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (flags&ONIGENC_CASE_ASCII_ONLY)
        rb_str_ascii_casemap(str, str, &flags, enc);
    else
        str_shared_replace(str, rb_str_casemap(str, &flags, enc));

    if (ONIGENC_CASE_MODIFIED&flags) return str;
    return Qnil;
}

#to_c ⇒ Complex

Returns self interpreted as a ::Complex object; leading whitespace and trailing garbage are ignored:

'9'.to_c                 # => (9+0i)
'2.5'.to_c               # => (2.5+0i)
'2.5/1'.to_c             # => ((5/2)+0i)
'-3/2'.to_c              # => ((-3/2)+0i)
'-i'.to_c                # => (0-1i)
'45i'.to_c               # => (0+45i)
'3-4i'.to_c              # => (3-4i)
'-4e2-4e-2i'.to_c        # => (-400.0-0.04i)
'-0.0-0.0i'.to_c         # => (-0.0-0.0i)
'1/2+3/4i'.to_c          # => ((1/2)+(3/4)*i)
'1.0@0'.to_c             # => (1+0.0i)
"1.0@#{Math::PI/2}".to_c # => (0.0+1i)
"1.0@#{Math::PI}".to_c   # => (-1+0.0i)

Returns Complex zero if the string cannot be converted:

'ruby'.to_c        # => (0+0i)

See Kernel.Complex.

[ GitHub ]

# File 'complex.c', line 2255


static VALUE
string_to_c(VALUE self)
{
    VALUE num;

    rb_must_asciicompat(self);

    (void)parse_comp(rb_str_fill_terminator(self, 1), FALSE, &num);

    return num;
}

#to_f ⇒ Float

Returns the result of interpreting leading characters in self as a ::Float:

'3.14159'.to_f  # => 3.14159
'1.234e-2'.to_f # => 0.01234

Characters past a leading valid number (in the given base) are ignored:

'3.14 (pi to two places)'.to_f # => 3.14

Returns zero if there is no leading valid number:

'abcdef'.to_f # => 0.0

[ GitHub ]

# File 'string.c', line 7174


static VALUE
rb_str_to_f(VALUE str)
{
    return DBL2NUM(rb_str_to_dbl(str, FALSE));
}

#to_i(base = 10) ⇒ Integer

Returns the result of interpreting leading characters in self as an integer in the given base (which must be in (0, 2..36)):

'123456'.to_i     # => 123456
'123def'.to_i(16) # => 1195503

With base zero, string object may contain leading characters to specify the actual base:

'123def'.to_i(0)   # => 123
'0123def'.to_i(0)  # => 83
'0b123def'.to_i(0) # => 1
'0o123def'.to_i(0) # => 83
'0d123def'.to_i(0) # => 123
'0x123def'.to_i(0) # => 1195503

Characters past a leading valid number (in the given base) are ignored:

'12.345'.to_i   # => 12
'12345'.to_i(2) # => 1

Returns zero if there is no leading valid number:

'abcdef'.to_i # => 0
'2'.to_i(2)   # => 0

[ GitHub ]

# File 'string.c', line 7143


static VALUE
rb_str_to_i(int argc, VALUE *argv, VALUE str)
{
    int base = 10;

    if (rb_check_arity(argc, 0, 1) && (base = NUM2INT(argv[0])) < 0) {
        rb_raise(rb_eArgError, "invalid radix %d", base);
    }
    return rb_str_to_inum(str, base, FALSE);
}

#to_r ⇒ Rational

Returns the result of interpreting leading characters in str as a rational. Leading whitespace and extraneous characters past the end of a valid number are ignored. Digit sequences can be separated by an underscore. If there is not a valid number at the start of str, zero is returned. This method never raises an exception.

'  2  '.to_r       #=> (2/1)
'300/2'.to_r       #=> (150/1)
'-9.2'.to_r        #=> (-46/5)
'-9.2e2'.to_r      #=> (-920/1)
'1_234_567'.to_r   #=> (1234567/1)
'21 June 09'.to_r  #=> (21/1)
'21/06/09'.to_r    #=> (7/2)
'BWV 1079'.to_r    #=> (0/1)

NOTE: “0.3”.to_r isn’t the same as 0.3.to_r. The former is equivalent to “3/10”.to_r, but the latter isn’t so.

"0.3".to_r == 3/10r  #=> true
0.3.to_r   == 3/10r  #=> false

#to_s ⇒ `self`, `String` Also known as: #to_str

Returns self if self is a String, or self converted to a String if self is a subclass of String.

[ GitHub ]

# File 'string.c', line 7189


static VALUE
rb_str_to_s(VALUE str)
{
    if (rb_obj_class(str) != rb_cString) {
        return str_duplicate(rb_cString, str);
    }
    return str;
}

#to_s ⇒ `self`, `String` #to_str ⇒ `self`, `String`

Alias for #to_s.

#intern ⇒ Symbol #to_sym ⇒ Symbol

Alias for #intern.

#tr(selector, replacements) ⇒ `String`

Returns a copy of self with each character specified by string selector translated to the corresponding character in string replacements. The correspondence is positional:

Each occurrence of the first character specified by selector is translated to the first character in replacements.
Each occurrence of the second character specified by selector is translated to the second character in replacements.
And so on.

Example:

'hello'.tr('el', 'ip') #=> "hippo"

If replacements is shorter than selector, it is implicitly padded with its own last character:

'hello'.tr('aeiou', '-')   # => "h-ll-"
'hello'.tr('aeiou', 'AA-') # => "hAll-"

Arguments selector and replacements must be valid character selectors (see Character Selectors), and may use any of its valid forms, including negation, ranges, and escaping:

# Negation.
'hello'.tr('^aeiou', '-') # => "-e--o"
# Ranges.
'ibm'.tr('b-z', 'a-z') # => "hal"
# Escapes.
'hel^lo'.tr('\^aeiou', '-')     # => "h-l-l-"    # Escaped leading caret.
'i-b-m'.tr('b\-z', 'a-z')       # => "ibabm"     # Escaped embedded hyphen.
'foo\\bar'.tr('ab\\', 'XYZ')    # => "fooZYXr"   # Escaped backslash.

[ GitHub ]

# File 'string.c', line 8783


static VALUE
rb_str_tr(VALUE str, VALUE src, VALUE repl)
{
    str = str_duplicate(rb_cString, str);
    tr_trans(str, src, repl, 0);
    return str;
}

#tr!(selector, replacements) ⇒ `self`^?

Like #tr, but modifies self in place. Returns self if any changes were made, nil otherwise.

[ GitHub ]

# File 'string.c', line 8737


static VALUE
rb_str_tr_bang(VALUE str, VALUE src, VALUE repl)
{
    return tr_trans(str, src, repl, 0);
}

#tr_s(selector, replacements) ⇒ `String`

Like #tr, but also squeezes the modified portions of the translated string; returns a new string (translated and squeezed).

'hello'.tr_s('l', 'r')   #=> "hero"
'hello'.tr_s('el', '-')  #=> "h-o"
'hello'.tr_s('el', 'hx') #=> "hhxo"

Related: #squeeze.

[ GitHub ]

# File 'string.c', line 9115


static VALUE
rb_str_tr_s(VALUE str, VALUE src, VALUE repl)
{
    str = str_duplicate(rb_cString, str);
    tr_trans(str, src, repl, 1);
    return str;
}

#tr_s!(selector, replacements) ⇒ `self`^?

Like #tr_s, but modifies self in place. Returns self if any changes were made, nil otherwise.

Related: #squeeze!.

[ GitHub ]

# File 'string.c', line 9093


static VALUE
rb_str_tr_s_bang(VALUE str, VALUE src, VALUE repl)
{
    return tr_trans(str, src, repl, 1);
}

#undump ⇒ `String`

Returns an unescaped version of self:

s_orig = "\f\x00\xff\\\""    # => "\f\u0000\xFF\\\""
s_dumped = s_orig.dump       # => "\"\\f\\x00\\xFF\\\\\\\"\""
s_undumped = s_dumped.undump # => "\f\u0000\xFF\\\""
s_undumped == s_orig         # => true

Related: #dump (inverse of undump).

[ GitHub ]

# File 'string.c', line 7737


static VALUE
str_undump(VALUE str)
{
    const char *s = RSTRING_PTR(str);
    const char *s_end = RSTRING_END(str);
    rb_encoding *enc = rb_enc_get(str);
    VALUE undumped = rb_enc_str_new(s, 0L, enc);
    bool utf8 = false;
    bool binary = false;
    int w;

    rb_must_asciicompat(str);
    if (rb_str_is_ascii_only_p(str) == Qfalse) {
        rb_raise(rb_eRuntimeError, "non-ASCII character detected");
    }
    if (!str_null_check(str, &w)) {
        rb_raise(rb_eRuntimeError, "string contains null byte");
    }
    if (RSTRING_LEN(str) < 2) goto invalid_format;
    if (*s != '"') goto invalid_format;

    /* strip '"' at the start */
    s++;

    for (;;) {
        if (s >= s_end) {
            rb_raise(rb_eRuntimeError, "unterminated dumped string");
        }

        if (*s == '"') {
            /* epilogue */
            s++;
            if (s == s_end) {
                /* ascii compatible dumped string */
                break;
            }
            else {
                static const char force_encoding_suffix[] = ".force_encoding(\""; /* "\")" */
                static const char dup_suffix[] = ".dup";
                const char *encname;
                int encidx;
                ptrdiff_t size;

                /* check separately for strings dumped by older versions */
                size = sizeof(dup_suffix) - 1;
                if (s_end - s > size && memcmp(s, dup_suffix, size) == 0) s += size;

                size = sizeof(force_encoding_suffix) - 1;
                if (s_end - s <= size) goto invalid_format;
                if (memcmp(s, force_encoding_suffix, size) != 0) goto invalid_format;
                s += size;

                if (utf8) {
                    rb_raise(rb_eRuntimeError, "dumped string contained Unicode escape but used force_encoding");
                }

                encname = s;
                s = memchr(s, '"', s_end-s);
                size = s - encname;
                if (!s) goto invalid_format;
                if (s_end - s != 2) goto invalid_format;
                if (s[0] != '"' || s[1] != ')') goto invalid_format;

                encidx = rb_enc_find_index2(encname, (long)size);
                if (encidx < 0) {
                    rb_raise(rb_eRuntimeError, "dumped string has unknown encoding name");
                }
                rb_enc_associate_index(undumped, encidx);
            }
            break;
        }

        if (*s == '\\') {
            s++;
            if (s >= s_end) {
                rb_raise(rb_eRuntimeError, "invalid escape");
            }
            undump_after_backslash(undumped, &s, s_end, &enc, &utf8, &binary);
        }
        else {
            rb_str_cat(undumped, s++, 1);
        }
    }

    RB_GC_GUARD(str);

    return undumped;
invalid_format:
    rb_raise(rb_eRuntimeError, "invalid dumped string; not wrapped with '\"' nor '\"...\".force_encoding(\"...\")' form");
}

#unicode_normalize(form = :nfc) ⇒ `String`

Returns a copy of self with Unicode normalization applied.

Argument form must be one of the following symbols (see Unicode normalization forms):

:nfc: Canonical decomposition, followed by canonical composition.
:nfd: Canonical decomposition.
:nfkc: Compatibility decomposition, followed by canonical composition.
:nfkd: Compatibility decomposition.

The encoding of self must be one of:

Encoding::UTF_8
Encoding::UTF_16BE
Encoding::UTF_16LE
Encoding::UTF_32BE
Encoding::UTF_32LE
Encoding::GB18030
Encoding::UCS_2BE
Encoding::UCS_4BE

Examples:

"a\u0300".unicode_normalize      # => "a"
"\u00E0".unicode_normalize(:nfd) # => "a "

[ GitHub ]

# File 'string.c', line 11997


static VALUE
rb_str_unicode_normalize(int argc, VALUE *argv, VALUE str)
{
    return unicode_normalize_common(argc, argv, str, id_normalize);
}

#unicode_normalize!(form = :nfc) ⇒ `self`

Like #unicode_normalize, except that the normalization is performed on self.

Related #unicode_normalized?.

[ GitHub ]

# File 'string.c', line 12013


static VALUE
rb_str_unicode_normalize_bang(int argc, VALUE *argv, VALUE str)
{
    return rb_str_replace(str, unicode_normalize_common(argc, argv, str, id_normalize));
}

#unicode_normalized?(form = :nfc) ⇒ `Boolean`

Returns true if self is in the given form of Unicode normalization, false otherwise. The form must be one of :nfc, :nfd, :nfkc, or :nfkd.

Examples:

"a\u0300".unicode_normalized?       # => false
"a\u0300".unicode_normalized?(:nfd) # => true
"\u00E0".unicode_normalized?        # => true
"\u00E0".unicode_normalized?(:nfd)  # => false

Raises an exception if self is not in a Unicode encoding:

s = "\xE0".force_encoding(Encoding::ISO_8859_1)
s.unicode_normalized? # Raises Encoding::CompatibilityError.

[ GitHub ]

# File 'string.c', line 12042


static VALUE
rb_str_unicode_normalized_p(int argc, VALUE *argv, VALUE str)
{
    return unicode_normalize_common(argc, argv, str, id_normalized_p);
}

#unpack(template, offset: 0, &block) ⇒ Array

Extracts data from self.

If block is not given, forming objects that become the elements of a new array, and returns that array. Otherwise, yields each object.

See Packed Data.

[ GitHub ]

# File 'pack.rb', line 23


def unpack(fmt, offset: 0)
  Primitive.attr! :use_block
  Primitive.pack_unpack(fmt, offset)
end

#unpack1(template, offset: 0) ⇒ Object

Like #unpack, but unpacks and returns only the first extracted object. See Packed Data.

[ GitHub ]

# File 'pack.rb', line 33


def unpack1(fmt, offset: 0)
  Primitive.pack_unpack1(fmt, offset)
end

#upcase(mapping) ⇒ `String`

Returns a string containing the upcased characters in self:

s = 'Hello World!' # => "Hello World!"
s.upcase           # => "HELLO WORLD!"

The casing may be affected by the given mapping; see Case Mapping.

Related: #upcase!, #downcase, #downcase!.

[ GitHub ]

# File 'string.c', line 8115


static VALUE
rb_str_upcase(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE;
    VALUE ret;

    flags = check_case_options(argc, argv, flags);
    enc = str_true_enc(str);
    if (case_option_single_p(flags, enc, str)) {
        ret = rb_str_new(RSTRING_PTR(str), RSTRING_LEN(str));
        str_enc_copy_direct(ret, str);
        upcase_single(ret);
    }
    else if (flags&ONIGENC_CASE_ASCII_ONLY) {
        ret = rb_str_new(0, RSTRING_LEN(str));
        rb_str_ascii_casemap(str, ret, &flags, enc);
    }
    else {
        ret = rb_str_casemap(str, &flags, enc);
    }

    return ret;
}

#upcase!(mapping) ⇒ `self`^?

Upcases the characters in self; returns self if any changes were made, nil otherwise:

s = 'Hello World!' # => "Hello World!"
s.upcase!          # => "HELLO WORLD!"
s                  # => "HELLO WORLD!"
s.upcase!          # => nil

The casing may be affected by the given mapping; see Case Mapping.

Related: #upcase, #downcase, #downcase!.

[ GitHub ]

# File 'string.c', line 8076


static VALUE
rb_str_upcase_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (case_option_single_p(flags, enc, str)) {
        if (upcase_single(str))
            flags |= ONIGENC_CASE_MODIFIED;
    }
    else if (flags&ONIGENC_CASE_ASCII_ONLY)
        rb_str_ascii_casemap(str, str, &flags, enc);
    else
        str_shared_replace(str, rb_str_casemap(str, &flags, enc));

    if (ONIGENC_CASE_MODIFIED&flags) return str;
    return Qnil;
}

#upto(other_string, exclusive = false) {|string| ... } ⇒ `self` #upto(other_string, exclusive = false) ⇒ Enumerator

With a block given, calls the block with each String value returned by successive calls to String#succ; the first value is self, the next is self.succ, and so on; the sequence terminates when value other_string is reached; returns self:

'a8'.upto('b6') {|s| print s, ' ' } # => "a8"

Output:

a8 a9 b0 b1 b2 b3 b4 b5 b6

If argument exclusive is given as a truthy object, the last value is omitted:

'a8'.upto('b6', true) {|s| print s, ' ' } # => "a8"

Output:

a8 a9 b0 b1 b2 b3 b4 b5

If other_string would not be reached, does not call the block:

'25'.upto('5') {|s| fail s }
'aa'.upto('a') {|s| fail s }

With no block given, returns a new ::Enumerator:

'a8'.upto('b6') # => #<Enumerator: "a8":upto("b6")>

[ GitHub ]

# File 'string.c', line 5579


static VALUE
rb_str_upto(int argc, VALUE *argv, VALUE beg)
{
    VALUE end, exclusive;

    rb_scan_args(argc, argv, "11", &end, &exclusive);
    RETURN_ENUMERATOR(beg, argc, argv);
    return rb_str_upto_each(beg, end, RTEST(exclusive), str_upto_i, Qnil);
}

Class: String

Overview

Substitution Methods

Whitespace in Strings

String Slices

What’s Here

Creating a String

Freezing/Unfreezing

Querying

Comparing

Modifying

Converting to New String

Converting to Non-String

Iterating

Class Method Summary

Instance Attribute Summary

Instance Method Summary

::Comparable - Included

Constructor Details

.new(*args)

#new(string = ''.encode(Encoding::ASCII_8BIT), **options) ⇒ String

Class Method Details

.try_convert(object) ⇒ Object, ...

Instance Attribute Details

#ascii_only? ⇒ Boolean (readonly)

#empty? ⇒ Boolean (readonly)

#valid_encoding? ⇒ Boolean (readonly)

Instance Method Details

#%(object) ⇒ String

#*(n) ⇒ String

#+(other_string) ⇒ String

#+ ⇒ String, self

#- ⇒ String Also known as: #dedup

#<<(object) ⇒ self

#<=>(other_string) ⇒ 1, ...

#==(object) ⇒ Boolean Also known as: #===

#==(object) ⇒ Boolean #===(object) ⇒ Boolean

#=~(object) ⇒ Integer?

#[](index) ⇒ String? #[](start, length) ⇒ String? #[](range) ⇒ String? #[](substring) ⇒ String? Also known as: #slice

#[]=(index, new_string) #[]=(start, length, new_string) #[]=(range, new_string) #[]=(substring, new_string)

#append_as_bytes(*objects) ⇒ self

#b ⇒ String

#byteindex(object, offset = 0) ⇒ Integer?

#byterindex(object, offset = self.bytesize) ⇒ Integer?

#bytes ⇒ array_of_bytes

#bytesize ⇒ Integer

#byteslice(offset, length = 1) ⇒ String? #byteslice(range) ⇒ String?

#bytesplice(offset, length, str) ⇒ self #bytesplice(offset, length, str, str_offset, str_length) ⇒ self #bytesplice(range, str) ⇒ self #bytesplice(range, str, str_range) ⇒ self

#capitalize(mapping = :ascii) ⇒ String

#capitalize!(mapping = :ascii) ⇒ self?

#casecmp(other_string) ⇒ 1, ...

#casecmp?(other_string) ⇒ true, ...

#center(size, pad_string = ' ') ⇒ String

#chars ⇒ array_of_characters

#chomp(line_sep = $/) ⇒ String

#chomp!(line_sep = $/) ⇒ self?

#chop ⇒ String

#chop! ⇒ self?

#chr ⇒ String

#clear ⇒ self

#codepoints ⇒ array_of_integers

#concat(*objects) ⇒ String

#count(*selectors) ⇒ Integer

#crypt(salt_str) ⇒ String

#- ⇒ String #dedup ⇒ String

#delete(*selectors) ⇒ String

#delete!(*selectors) ⇒ self?

#delete_prefix(prefix) ⇒ String

#delete_prefix!(prefix) ⇒ self?

#delete_suffix(suffix) ⇒ String

#delete_suffix!(suffix) ⇒ self?

#downcase(mapping) ⇒ String

#downcase!(mapping) ⇒ self?

#dump ⇒ String

#dup

#each_byte {|byte| ... } ⇒ self #each_byte ⇒ Enumerator

#each_char {|c| ... } ⇒ self #each_char ⇒ Enumerator

#each_codepoint {|integer| ... } ⇒ self #each_codepoint ⇒ Enumerator

#each_grapheme_cluster {|gc| ... } ⇒ self #each_grapheme_cluster ⇒ Enumerator

#each_line(line_sep = $/, chomp: false) {|substring| ... } ⇒ self #each_line(line_sep = $/, chomp: false) ⇒ Enumerator

`String` Slices

`::Comparable` - Included

#new(string = ''.encode(Encoding::ASCII_8BIT), **options) ⇒ `String`

#ascii_only? ⇒ `Boolean` (readonly)

#empty? ⇒ `Boolean` (readonly)

#valid_encoding? ⇒ `Boolean` (readonly)

#%(object) ⇒ `String`

#*(n) ⇒ `String`

#+(other_string) ⇒ `String`

#+ ⇒ `String`, `self`

#- ⇒ `String` Also known as: #dedup

#<<(object) ⇒ `self`

#<=>(other_string) ⇒ `1`, ...

#==(object) ⇒ `Boolean` Also known as: #===

#==(object) ⇒ `Boolean` #===(object) ⇒ `Boolean`

#=~(object) ⇒ Integer^?

#[](index) ⇒ `String`^? #[](start, length) ⇒ `String`^? #[](range) ⇒ `String`^? #[](substring) ⇒ `String`^?
Also known as: #slice

#append_as_bytes(*objects) ⇒ `self`

#b ⇒ `String`

#byteindex(object, offset = 0) ⇒ Integer^?

#byterindex(object, offset = self.bytesize) ⇒ Integer^?

#bytes ⇒ `array_of_bytes`

#byteslice(offset, length = 1) ⇒ `String`^? #byteslice(range) ⇒ `String`^?

#bytesplice(offset, length, str) ⇒ `self` #bytesplice(offset, length, str, str_offset, str_length) ⇒ `self` #bytesplice(range, str) ⇒ `self` #bytesplice(range, str, str_range) ⇒ `self`

#capitalize(mapping = :ascii) ⇒ `String`

#capitalize!(mapping = :ascii) ⇒ `self`^?

#casecmp(other_string) ⇒ `1`, ...

#casecmp?(other_string) ⇒ `true`, ...

#center(size, pad_string = ' ') ⇒ `String`

#chars ⇒ `array_of_characters`

#chomp(line_sep = $/) ⇒ `String`

#chomp!(line_sep = $/) ⇒ `self`^?

#chop ⇒ `String`

#chop! ⇒ `self`^?

#chr ⇒ `String`

#clear ⇒ `self`

#codepoints ⇒ `array_of_integers`

#concat(*objects) ⇒ `String`

#crypt(salt_str) ⇒ `String`

#- ⇒ `String` #dedup ⇒ `String`

#delete(*selectors) ⇒ `String`

#delete!(*selectors) ⇒ `self`^?

#delete_prefix(prefix) ⇒ `String`

#delete_prefix!(prefix) ⇒ `self`^?

#delete_suffix(suffix) ⇒ `String`

#delete_suffix!(suffix) ⇒ `self`^?

#downcase(mapping) ⇒ `String`

#downcase!(mapping) ⇒ `self`^?

#dump ⇒ `String`

#each_byte {|byte| ... } ⇒ `self` #each_byte ⇒ Enumerator

#each_char {|c| ... } ⇒ `self` #each_char ⇒ Enumerator

#each_codepoint {|integer| ... } ⇒ `self` #each_codepoint ⇒ Enumerator

#each_grapheme_cluster {|gc| ... } ⇒ `self` #each_grapheme_cluster ⇒ Enumerator

#each_line(line_sep = $/, chomp: false) {|substring| ... } ⇒ `self` #each_line(line_sep = $/, chomp: false) ⇒ Enumerator

#encode(dst_encoding = Encoding.default_internal, enc_opts) ⇒ `String` #encode(dst_encoding, src_encoding, enc_opts) ⇒ `String`

#encode!(dst_encoding = Encoding.default_internal, enc_opts) ⇒ `self` #encode!(dst_encoding, src_encoding, enc_opts) ⇒ `self`

#end_with?(*strings) ⇒ `Boolean`

#eql?(object) ⇒ `Boolean`

#force_encoding(encoding) ⇒ `self`

#getbyte(index) ⇒ Integer^?

#grapheme_clusters ⇒ `array_of_grapheme_clusters`

#gsub(pattern, replacement) ⇒ `String` #gsub(pattern) {|match| ... } ⇒ `String` #gsub(pattern) ⇒ Enumerator

#gsub!(pattern, replacement) ⇒ `self`^? #gsub!(pattern) {|match| ... } ⇒ `self`^? #gsub!(pattern) ⇒ Enumerator

#include?(other_string) ⇒ `Boolean`

#index(substring, offset = 0) ⇒ Integer^? #index(regexp, offset = 0) ⇒ Integer^?

#replace(other_string) ⇒ `self` #initialize_copy(other_string) ⇒ `self`

#insert(index, other_string) ⇒ `self`

#inspect ⇒ `String`

#intern ⇒ Symbol #to_sym ⇒ Symbol
Also known as: #to_sym

#lines(Line_sep = $/, chomp: false) ⇒ `String`

#ljust(size, pad_string = ' ') ⇒ `String`

#lstrip ⇒ `String`

#lstrip! ⇒ `self`^?

#match(pattern, offset = 0) ⇒ MatchData^? #match(pattern, offset = 0) {|matchdata| ... } ⇒ Object

#match?(pattern, offset = 0) ⇒ `Boolean`

#next ⇒ `String` Also known as: #succ

#next! ⇒ `self` Also known as: #succ!

#prepend(*other_strings) ⇒ `String`

#replace(other_string) ⇒ `self` Also known as: #initialize_copy

#reverse ⇒ `String`