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Class: Hash

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, ::Enumerable
Inherits: Object
Defined in: hash.c,
hash.rb

Class Method Summary

Instance Attribute Summary

Instance Method Summary

::Enumerable - Included

#all?

Returns whether every element meets a given criterion.
#any?

Returns whether any element meets a given criterion.
#chain

Returns an enumerator object generated from this enumerator and given enumerables.
#chunk

Each element in the returned enumerator is a 2-element array consisting of:
#chunk_while

Creates an enumerator for each chunked elements.
#collect

Alias for Enumerable#map.
#collect_concat

Alias for Enumerable#flat_map.
#compact

Returns an array of all non-nil elements:
#count

Returns the count of elements, based on an argument or block criterion, if given.
#cycle

When called with positive integer argument n and a block, calls the block with each element, then does so again, until it has done so n times; returns nil:
#detect

Alias for Enumerable#find.
#drop

For positive integer n, returns an array containing all but the first n elements:
#drop_while

Calls the block with successive elements as long as the block returns a truthy value; returns an array of all elements after that point:
#each_cons

Calls the block with each successive overlapped n-tuple of elements; returns self:
#each_entry

Calls the given block with each element, converting multiple values from yield to an array; returns self:
#each_slice

Calls the block with each successive disjoint n-tuple of elements; returns self:
#each_with_index

Invoke self.each with *args.
#each_with_object

Calls the block once for each element, passing both the element and the given object:
#entries

Alias for Enumerable#to_a.
#filter

Returns an array containing elements selected by the block.
#filter_map

Returns an array containing truthy elements returned by the block.
#find

Returns the first element for which the block returns a truthy value.
#find_all

Alias for Enumerable#filter.
#find_index

Returns the index of the first element that meets a specified criterion, or nil if no such element is found.
#first

Returns the first element or elements.
#flat_map

Returns an array of flattened objects returned by the block.
#grep

Returns an array of objects based elements of self that match the given pattern.
#grep_v

Returns an array of objects based on elements of self that don’t match the given pattern.
#group_by

With a block given returns a hash:
#include?

Alias for Enumerable#member?.
#inject

Returns the result of applying a reducer to an initial value and the first element of the ::Enumerable.
#lazy

Returns an ::Enumerator::Lazy, which redefines most ::Enumerable methods to postpone enumeration and enumerate values only on an as-needed basis.
#map

Returns an array of objects returned by the block.
#max

Returns the element with the maximum element according to a given criterion.
#max_by

Returns the elements for which the block returns the maximum values.
#member?

Returns whether for any element object == element:
#min

Returns the element with the minimum element according to a given criterion.
#min_by

Returns the elements for which the block returns the minimum values.
#minmax

Returns a 2-element array containing the minimum and maximum elements according to a given criterion.
#minmax_by

Returns a 2-element array containing the elements for which the block returns minimum and maximum values:
#none?

Returns whether no element meets a given criterion.
#one?

Returns whether exactly one element meets a given criterion.
#partition

With a block given, returns an array of two arrays:
#reduce

Alias for Enumerable#inject.
#reject

Returns an array of objects rejected by the block.
#reverse_each

With a block given, calls the block with each element, but in reverse order; returns self:
#select

Alias for Enumerable#filter.
#slice_after

Creates an enumerator for each chunked elements.
#slice_before

With argument pattern, returns an enumerator that uses the pattern to partition elements into arrays (“slices”).
#slice_when

Creates an enumerator for each chunked elements.
#sort

Returns an array containing the sorted elements of self.
#sort_by

With a block given, returns an array of elements of self, sorted according to the value returned by the block for each element.
#sum

With no block given, returns the sum of initial_value and the elements:
#take

For non-negative integer n, returns the first n elements:
#take_while

Calls the block with successive elements as long as the block returns a truthy value; returns an array of all elements up to that point:
#tally

When argument #hash is not given, returns a new hash whose keys are the distinct elements in self; each integer value is the count of occurrences of each element:
#to_a

Returns an array containing the items in self:
#to_h

When self consists of 2-element arrays, returns a hash each of whose entries is the key-value pair formed from one of those arrays:
#to_set

Makes a set from the enumerable object with given arguments.
#uniq

With no block, returns a new array containing only unique elements; the array has no two elements e0 and e1 such that e0.eql?(e1):
#zip

With no block given, returns a new array new_array of size self.size whose elements are arrays.

Constructor Details

.new(default_value = nil) ⇒ Hash .new(default_value = nil, capacity: size) ⇒ Hash .new {|hash, key| ... } ⇒ Hash .new(capacity: size) {|hash, key| ... } ⇒ Hash

Returns a new empty Hash object.

The initial default value and initial default proc for the new hash depend on which form above was used. See Default Values.

If neither an argument nor a block is given, initializes both the default value and the default proc to nil:

h = Hash.new
h.default # => nil
h.default_proc # => nil

If argument default_value is given but no block is given, initializes the default value to the given default_value and the default proc to nil:

h = Hash.new(false)
h.default # => false
h.default_proc # => nil

If a block is given but no default_value, stores the block as the default proc and sets the default value to nil:

h = Hash.new {|hash, key| "Default value for #{key}" }
h.default # => nil
h.default_proc.class # => Proc
h[:nosuch] # => "Default value for nosuch"

If both a block and a default_value are given, raises an ::ArgumentError

If the optional keyword argument capacity is given, the hash will be allocated with enough capacity to accommodate this many keys without having to be resized.

[ GitHub ] 

  


# File 'hash.rb', line 37



def initialize(ifnone = (ifnone_unset = true), capacity: 0, &block)
  Primitive.rb_hash_init(capacity, ifnone_unset, ifnone, block)
end


  







Class Method Details



  

    

      .[]  ⇒ Hash 
      .[](hash)  ⇒ Hash 
      .[]([*2_element_arrays] )  ⇒ Hash 
      .[](*objects)  ⇒ Hash 
    

  



  

    

Returns a new Hash object populated with the given objects, if any. See .new.



With no argument, returns a new empty Hash.



When the single given argument is a Hash, returns a new Hash populated with the entries from the given Hash, excluding the default value or proc.



h = {foo: 0, bar: 1, baz: 2}
Hash[h] # => {:foo=>0, :bar=>1, :baz=>2}



When the single given argument is an ::Array of 2-element Arrays, returns a new Hash object wherein each 2-element array forms a key-value entry:



Hash[ [ [:foo, 0], [:bar, 1] ] ] # => {:foo=>0, :bar=>1}



When the argument count is an even number; returns a new Hash object wherein each successive pair of arguments has become a key-value entry:



Hash[:foo, 0, :bar, 1] # => {:foo=>0, :bar=>1}



Raises an exception if the argument list does not conform to any of the above.


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 1826



static VALUE
rb_hash_s_create(int argc, VALUE *argv, VALUE klass)
{
    VALUE hash, tmp;

    if (argc == 1) {
        tmp = rb_hash_s_try_convert(Qnil, argv[0]);
        if (!NIL_P(tmp)) {
            if (!RHASH_EMPTY_P(tmp)  && rb_hash_compare_by_id_p(tmp)) {
                /* hash_copy for non-empty hash will copy compare_by_identity
                   flag, but we don't want it copied. Work around by
                   converting hash to flattened array and using that. */
                tmp = rb_hash_to_a(tmp);
            }
            else {
                hash = hash_alloc(klass);
                if (!RHASH_EMPTY_P(tmp))
                    hash_copy(hash, tmp);
                return hash;
            }
        }
        else {
            tmp = rb_check_array_type(argv[0]);
        }

        if (!NIL_P(tmp)) {
            long i;

            hash = hash_alloc(klass);
            for (i = 0; i < RARRAY_LEN(tmp); ++i) {
                VALUE e = RARRAY_AREF(tmp, i);
                VALUE v = rb_check_array_type(e);
                VALUE key, val = Qnil;

                if (NIL_P(v)) {
                    rb_raise(rb_eArgError, "wrong element type %s at %ld (expected array)",
                             rb_builtin_class_name(e), i);
                }
                switch (RARRAY_LEN(v)) {
                  default:
                    rb_raise(rb_eArgError, "invalid number of elements (%ld for 1..2)",
                             RARRAY_LEN(v));
                  case 2:
                    val = RARRAY_AREF(v, 1);
                  case 1:
                    key = RARRAY_AREF(v, 0);
                    rb_hash_aset(hash, key, val);
                }
            }
            return hash;
        }
    }
    if (argc % 2 != 0) {
        rb_raise(rb_eArgError, "odd number of arguments for Hash");
    }

    hash = hash_alloc(klass);
    rb_hash_bulk_insert(argc, argv, hash);
    hash_verify(hash);
    return hash;
}


  








  

    .ruby2_keywords_hash(hash)  ⇒ Hash   



  

    

Duplicates a given hash and adds a ruby2_keywords flag. This method is not for casual use; debugging, researching, and some truly necessary cases like deserialization of arguments.



h = {k: 1}
h = Hash.ruby2_keywords_hash(h)
def foo(k: 42)
  k
end
foo(*[h]) #=> 1 with neither a warning or an error


  



  [ GitHub ]


  

  


# File 'hash.c', line 1957



static VALUE
rb_hash_s_ruby2_keywords_hash(VALUE dummy, VALUE hash)
{
    Check_Type(hash, T_HASH);
    VALUE tmp = rb_hash_dup(hash);
    if (RHASH_EMPTY_P(hash) && rb_hash_compare_by_id_p(hash)) {
        rb_hash_compare_by_id(tmp);
    }
    RHASH(tmp)->basic.flags |= RHASH_PASS_AS_KEYWORDS;
    return tmp;
}


  








  

    .ruby2_keywords_hash?(hash)  ⇒ Boolean   



  

    

Checks if a given hash is flagged by Module#ruby2_keywords (or Proc#ruby2_keywords). This method is not for casual use; debugging, researching, and some truly necessary cases like serialization of arguments.



ruby2_keywords def foo(*args)
  Hash.ruby2_keywords_hash?(args.last)
end
foo(k: 1)   #=> true
foo({k: 1}) #=> false


  



  [ GitHub ]


  

  


# File 'hash.c', line 1935



static VALUE
rb_hash_s_ruby2_keywords_hash_p(VALUE dummy, VALUE hash)
{
    Check_Type(hash, T_HASH);
    return RBOOL(RHASH(hash)->basic.flags & RHASH_PASS_AS_KEYWORDS);
}


  








  

    .try_convert(obj)  ⇒ Object, ...   



  

    

If obj is a Hash object, returns obj.



Otherwise if obj responds to :to_hash, calls obj.to_hash and returns the result.



Returns nil if obj does not respond to :to_hash



Raises an exception unless obj.to_hash returns a Hash object.


  



  [ GitHub ]


  

  


# File 'hash.c', line 1914



static VALUE
rb_hash_s_try_convert(VALUE dummy, VALUE hash)
{
    return rb_check_hash_type(hash);
}


  







Instance Attribute Details



  

    #compare_by_identity  ⇒ self  (readonly)  



  

    

Sets self to consider only identity in comparing keys; two keys are considered the same only if they are the same object; returns self.



By default, these two object are considered to be the same key, so s1 will overwrite s0:



s0 = 'x'
s1 = 'x'
h = {}
h.compare_by_identity? # => false
h[s0] = 0
h[s1] = 1
h # => {"x"=>1}



After calling #compare_by_identity, the keys are considered to be different, and therefore do not overwrite each other:



h = {}
h.compare_by_identity # => {}
h.compare_by_identity? # => true
h[s0] = 0
h[s1] = 1
h # => {"x"=>0, "x"=>1}


  



  [ GitHub ]


  

  


# File 'hash.c', line 4403



VALUE
rb_hash_compare_by_id(VALUE hash)
{
    VALUE tmp;
    st_table *identtable;

    if (rb_hash_compare_by_id_p(hash)) return hash;

    rb_hash_modify_check(hash);
    if (hash_iterating_p(hash)) {
        rb_raise(rb_eRuntimeError, "compare_by_identity during iteration");
    }

    if (RHASH_TABLE_EMPTY_P(hash)) {
        // Fast path: There's nothing to rehash, so we don't need a `tmp` table.
        // We're most likely an AR table, so this will need an allocation.
        ar_force_convert_table(hash, __FILE__, __LINE__);
        HASH_ASSERT(RHASH_ST_TABLE_P(hash));

        RHASH_ST_TABLE(hash)->type = &identhash;
    }
    else {
        // Slow path: Need to rehash the members of `self` into a new
        // `tmp` table using the new `identhash` compare/hash functions.
        tmp = hash_alloc(0);
        hash_st_table_init(tmp, &identhash, RHASH_SIZE(hash));
        identtable = RHASH_ST_TABLE(tmp);

        rb_hash_foreach(hash, rb_hash_rehash_i, (VALUE)tmp);
        rb_hash_free(hash);

        // We know for sure `identtable` is an st table,
        // so we can skip `ar_force_convert_table` here.
        RHASH_ST_TABLE_SET(hash, identtable);
        RHASH_ST_CLEAR(tmp);
    }

    return hash;
}


  








  

    #compare_by_identity?  ⇒ Boolean  (readonly)  



  

    

Returns true if #compare_by_identity has been called, false otherwise.


  



  [ GitHub ]


  

  


# File 'hash.c', line 4450



VALUE
rb_hash_compare_by_id_p(VALUE hash)
{
    return RBOOL(RHASH_IDENTHASH_P(hash));
}


  








  

    #default_proc  ⇒ Proc?  (rw)  



  

    

Returns the default proc for self (see Default Values):



h = {}
h.default_proc # => nil
h.default_proc = proc {|hash, key| "Default value for #{key}" }
h.default_proc.class # => Proc


  



  [ GitHub ]


  

  


# File 'hash.c', line 2268



static VALUE
rb_hash_default_proc(VALUE hash)
{
    if (FL_TEST(hash, RHASH_PROC_DEFAULT)) {
        return RHASH_IFNONE(hash);
    }
    return Qnil;
}


  








  

    #default_proc=(proc)  ⇒ Proc  (rw)  



  

    

Sets the default proc for self to proc (see Default Values):



h = {}
h.default_proc # => nil
h.default_proc = proc { |hash, key| "Default value for #{key}" }
h.default_proc.class # => Proc
h.default_proc = nil
h.default_proc # => nil


  



  [ GitHub ]


  

  


# File 'hash.c', line 2291



VALUE
rb_hash_set_default_proc(VALUE hash, VALUE proc)
{
    VALUE b;

    rb_hash_modify_check(hash);
    if (NIL_P(proc)) {
        SET_DEFAULT(hash, proc);
        return proc;
    }
    b = rb_check_convert_type_with_id(proc, T_DATA, "Proc", idTo_proc);
    if (NIL_P(b) || !rb_obj_is_proc(b)) {
        rb_raise(rb_eTypeError,
                 "wrong default_proc type %s (expected Proc)",
                 rb_obj_classname(proc));
    }
    proc = b;
    SET_PROC_DEFAULT(hash, proc);
    return proc;
}


  








  

    #empty?  ⇒ Boolean  (readonly)  



  

    

Returns true if there are no hash entries, false otherwise:



{}.empty? # => true
{foo: 0, bar: 1, baz: 2}.empty? # => false


  



  [ GitHub ]


  

  


# File 'hash.c', line 3006



VALUE
rb_hash_empty_p(VALUE hash)
{
    return RBOOL(RHASH_EMPTY_P(hash));
}


  







Instance Method Details



  

    #<(other_hash)  ⇒ Boolean   



  

    

Returns true if #hash is a proper subset of other_hash, false otherwise:



h1 = {foo: 0, bar: 1}
h2 = {foo: 0, bar: 1, baz: 2}
h1 < h2 # => true
h2 < h1 # => false
h1 < h1 # => false


  



  [ GitHub ]


  

  


# File 'hash.c', line 4663



static VALUE
rb_hash_lt(VALUE hash, VALUE other)
{
    other = to_hash(other);
    if (RHASH_SIZE(hash) >= RHASH_SIZE(other)) return Qfalse;
    return hash_le(hash, other);
}


  








  

    #<=(other_hash)  ⇒ Boolean   



  

    

Returns true if #hash is a subset of other_hash, false otherwise:



h1 = {foo: 0, bar: 1}
h2 = {foo: 0, bar: 1, baz: 2}
h1 <= h2 # => true
h2 <= h1 # => false
h1 <= h1 # => true


  



  [ GitHub ]


  

  


# File 'hash.c', line 4644



static VALUE
rb_hash_le(VALUE hash, VALUE other)
{
    other = to_hash(other);
    if (RHASH_SIZE(hash) > RHASH_SIZE(other)) return Qfalse;
    return hash_le(hash, other);
}


  








  

    #==(object)  ⇒ Boolean   



  

    

Returns true if all of the following are true:


  • 

    object is a Hash object.
    

  • 

    #hash and object have the same keys (regardless of order).
    

  • 

    For each key #key, hash[key] == object[key].
    




Otherwise, returns false.



Equal:



h1 = {foo: 0, bar: 1, baz: 2}
h2 = {foo: 0, bar: 1, baz: 2}
h1 == h2 # => true
h3 = {baz: 2, bar: 1, foo: 0}
h1 == h3 # => true


  



  [ GitHub ]


  

  


# File 'hash.c', line 3822



static VALUE
rb_hash_equal(VALUE hash1, VALUE hash2)
{
    return hash_equal(hash1, hash2, FALSE);
}


  








  

    #>(other_hash)  ⇒ Boolean   



  

    

Returns true if #hash is a proper superset of other_hash, false otherwise:



h1 = {foo: 0, bar: 1, baz: 2}
h2 = {foo: 0, bar: 1}
h1 > h2 # => true
h2 > h1 # => false
h1 > h1 # => false


  



  [ GitHub ]


  

  


# File 'hash.c', line 4701



static VALUE
rb_hash_gt(VALUE hash, VALUE other)
{
    other = to_hash(other);
    if (RHASH_SIZE(hash) <= RHASH_SIZE(other)) return Qfalse;
    return hash_le(other, hash);
}


  








  

    #>=(other_hash)  ⇒ Boolean   



  

    

Returns true if #hash is a superset of other_hash, false otherwise:



h1 = {foo: 0, bar: 1, baz: 2}
h2 = {foo: 0, bar: 1}
h1 >= h2 # => true
h2 >= h1 # => false
h1 >= h1 # => true


  



  [ GitHub ]


  

  


# File 'hash.c', line 4682



static VALUE
rb_hash_ge(VALUE hash, VALUE other)
{
    other = to_hash(other);
    if (RHASH_SIZE(hash) < RHASH_SIZE(other)) return Qfalse;
    return hash_le(other, hash);
}


  








  

    #[](key)  ⇒ value   



  

    

Returns the value associated with the given #key, if found:



h = {foo: 0, bar: 1, baz: 2}
h[:foo] # => 0



If #key is not found, returns a default value (see Default Values):



h = {foo: 0, bar: 1, baz: 2}
h[:nosuch] # => nil


  



  [ GitHub ]


  

  


# File 'hash.c', line 2104



VALUE
rb_hash_aref(VALUE hash, VALUE key)
{
    st_data_t val;

    if (hash_stlike_lookup(hash, key, &val)) {
        return (VALUE)val;
    }
    else {
        return rb_hash_default_value(hash, key);
    }
}


  








  

    

      #[]=(key, value)  ⇒ value 
      #store(key, value)  
    

    Also known as: #store
  



  

    

Associates the given value with the given #key; returns value.



If the given #key exists, replaces its value with the given value; the ordering is not affected (see Entry Order):



h = {foo: 0, bar: 1}
h[:foo] = 2 # => 2
h.store(:bar, 3) # => 3
h # => {:foo=>2, :bar=>3}



If #key does not exist, adds the #key and value; the new entry is last in the order (see Entry Order):



h = {foo: 0, bar: 1}
h[:baz] = 2 # => 2
h.store(:bat, 3) # => 3
h # => {:foo=>0, :bar=>1, :baz=>2, :bat=>3}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2924



VALUE
rb_hash_aset(VALUE hash, VALUE key, VALUE val)
{
    bool iter_p = hash_iterating_p(hash);

    rb_hash_modify(hash);

    if (!RHASH_STRING_KEY_P(hash, key)) {
        RHASH_UPDATE_ITER(hash, iter_p, key, hash_aset, val);
    }
    else {
        RHASH_UPDATE_ITER(hash, iter_p, key, hash_aset_str, val);
    }
    return val;
}


  








  

    

      #any?  ⇒ Boolean 
      #any?(object)  ⇒ Boolean 
      #any? {|key, value| ... } ⇒ Boolean 
    

  



  

    

Returns true if any element satisfies a given criterion; false otherwise.



If self has no element, returns false and argument or block are not used.



With no argument and no block, returns true if self is non-empty; false if empty.



With argument object and no block, returns true if for any key #key h.assoc(key) == object:



h = {foo: 0, bar: 1, baz: 2}
h.any?([:bar, 1]) # => true
h.any?([:bar, 0]) # => false
h.any?([:baz, 1]) # => false



With no argument and a block, calls the block with each key-value pair; returns true if the block returns any truthy value, false otherwise:



h = {foo: 0, bar: 1, baz: 2}
h.any? {|key, value| value < 3 } # => true
h.any? {|key, value| value > 3 } # => false



Related: Enumerable#any?


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 4545



static VALUE
rb_hash_any_p(int argc, VALUE *argv, VALUE hash)
{
    VALUE args[2];
    args[0] = Qfalse;

    rb_check_arity(argc, 0, 1);
    if (RHASH_EMPTY_P(hash)) return Qfalse;
    if (argc) {
        if (rb_block_given_p()) {
            rb_warn("given block not used");
        }
        args[1] = argv[0];

        rb_hash_foreach(hash, any_p_i_pattern, (VALUE)args);
    }
    else {
        if (!rb_block_given_p()) {
            /* yields pairs, never false */
            return Qtrue;
        }
        if (rb_block_pair_yield_optimizable())
            rb_hash_foreach(hash, any_p_i_fast, (VALUE)args);
        else
            rb_hash_foreach(hash, any_p_i, (VALUE)args);
    }
    return args[0];
}


  








  

    #assoc(key)  ⇒ Array?   



  

    

If the given #key is found, returns a 2-element ::Array containing that key and its value:



h = {foo: 0, bar: 1, baz: 2}
h.assoc(:bar) # => [:bar, 1]



Returns nil if key #key is not found.


  



  [ GitHub ]


  

  


# File 'hash.c', line 4169



static VALUE
rb_hash_assoc(VALUE hash, VALUE key)
{
    VALUE args[2];

    if (RHASH_EMPTY_P(hash)) return Qnil;

    if (RHASH_ST_TABLE_P(hash) && !RHASH_IDENTHASH_P(hash)) {
        VALUE value = Qundef;
        st_table assoctable = *RHASH_ST_TABLE(hash);
        assoctable.type = &(struct st_hash_type){
            .compare = assoc_cmp,
            .hash = assoctable.type->hash,
        };
        VALUE arg = (VALUE)&(struct assoc_arg){
            .tbl = &assoctable,
            .key = (st_data_t)key,
        };

        if (RB_OBJ_FROZEN(hash)) {
            value = assoc_lookup(arg);
        }
        else {
            hash_iter_lev_inc(hash);
            value = rb_ensure(assoc_lookup, arg, hash_foreach_ensure, hash);
        }
        hash_verify(hash);
        if (!UNDEF_P(value)) return rb_assoc_new(key, value);
    }

    args[0] = key;
    args[1] = Qnil;
    rb_hash_foreach(hash, assoc_i, (VALUE)args);
    return args[1];
}


  








  

    #clear  ⇒ self   



  

    

Removes all hash entries; returns self.


  



  [ GitHub ]


  

  


# File 'hash.c', line 2851



VALUE
rb_hash_clear(VALUE hash)
{
    rb_hash_modify_check(hash);

    if (hash_iterating_p(hash)) {
        rb_hash_foreach(hash, clear_i, 0);
    }
    else if (RHASH_AR_TABLE_P(hash)) {
        ar_clear(hash);
    }
    else {
        st_clear(RHASH_ST_TABLE(hash));
        compact_after_delete(hash);
    }

    return hash;
}


  








  

    #compact  ⇒ Hash   



  

    

Returns a copy of self with all nil-valued entries removed:



h = {foo: 0, bar: nil, baz: 2, bat: nil}
h1 = h.compact
h1 # => {:foo=>0, :baz=>2}


  



  [ GitHub ]


  

  


# File 'hash.c', line 4336



static VALUE
rb_hash_compact(VALUE hash)
{
    VALUE result = rb_hash_dup(hash);
    if (!RHASH_EMPTY_P(hash)) {
        rb_hash_foreach(result, delete_if_nil, result);
        compact_after_delete(result);
    }
    else if (rb_hash_compare_by_id_p(hash)) {
        result = rb_hash_compare_by_id(result);
    }
    return result;
}


  








  

    #compact!  ⇒ self?   



  

    

Returns self with all its nil-valued entries removed (in place):



h = {foo: 0, bar: nil, baz: 2, bat: nil}
h.compact! # => {:foo=>0, :baz=>2}



Returns nil if no entries were removed.


  



  [ GitHub ]


  

  


# File 'hash.c', line 4361



static VALUE
rb_hash_compact_bang(VALUE hash)
{
    st_index_t n;
    rb_hash_modify_check(hash);
    n = RHASH_SIZE(hash);
    if (n) {
        rb_hash_foreach(hash, delete_if_nil, hash);
        if (n != RHASH_SIZE(hash))
            return hash;
    }
    return Qnil;
}


  








  

    #deconstruct_keys(keys)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'hash.c', line 4735



static VALUE
rb_hash_deconstruct_keys(VALUE hash, VALUE keys)
{
    return hash;
}


  








  

    

      #default  ⇒ Object 
      #default(key)  ⇒ Object 
    

  



  

    

Returns the default value for the given #key. The returned value will be determined either by the default proc or by the default value. See Default Values.



With no argument, returns the current default value:



h = {}
h.default # => nil



If #key is given, returns the default value for #key, regardless of whether that key exists:



h = Hash.new { |hash, key| hash[key] = "No key #{key}"}
h[:foo] = "Hello"
h.default(:foo) # => "No key foo"


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2221



static VALUE
rb_hash_default(int argc, VALUE *argv, VALUE hash)
{
    VALUE ifnone;

    rb_check_arity(argc, 0, 1);
    ifnone = RHASH_IFNONE(hash);
    if (FL_TEST(hash, RHASH_PROC_DEFAULT)) {
        if (argc == 0) return Qnil;
        return call_default_proc(ifnone, hash, argv[0]);
    }
    return ifnone;
}


  








  

    #default=(value)  ⇒ Object   



  

    

Sets the default value to value; returns value:



h = {}
h.default # => nil
h.default = false # => false
h.default # => false



See Default Values.


  



  [ GitHub ]


  

  


# File 'hash.c', line 2248



static VALUE
rb_hash_set_default(VALUE hash, VALUE ifnone)
{
    rb_hash_modify_check(hash);
    SET_DEFAULT(hash, ifnone);
    return ifnone;
}


  








  

    

      #delete(key)  ⇒ value? 
      #delete(key) {|key| ... } ⇒ Object 
    

  



  

    

Deletes the entry for the given #key and returns its associated value.



If no block is given and #key is found, deletes the entry and returns the associated value:



h = {foo: 0, bar: 1, baz: 2}
h.delete(:bar) # => 1
h # => {:foo=>0, :baz=>2}



If no block given and #key is not found, returns nil.



If a block is given and #key is found, ignores the block, deletes the entry, and returns the associated value:



h = {foo: 0, bar: 1, baz: 2}
h.delete(:baz) { |key| raise 'Will never happen'} # => 2
h # => {:foo=>0, :bar=>1}



If a block is given and #key is not found, calls the block and returns the block’s return value:



h = {foo: 0, bar: 1, baz: 2}
h.delete(:nosuch) { |key| "Key #{key} not found" } # => "Key nosuch not found"
h # => {:foo=>0, :bar=>1, :baz=>2}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2424



static VALUE
rb_hash_delete_m(VALUE hash, VALUE key)
{
    VALUE val;

    rb_hash_modify_check(hash);
    val = rb_hash_delete_entry(hash, key);

    if (!UNDEF_P(val)) {
        compact_after_delete(hash);
        return val;
    }
    else {
        if (rb_block_given_p()) {
            return rb_yield(key);
        }
        else {
            return Qnil;
        }
    }
}


  








  

    

      #delete_if {|key, value| ... } ⇒ self 
      #delete_if  ⇒ Enumerator 
    

  



  

    

If a block given, calls the block with each key-value pair; deletes each entry for which the block returns a truthy value; returns self:



h = {foo: 0, bar: 1, baz: 2}
h.delete_if {|key, value| value > 0 } # => {:foo=>0}



If no block given, returns a new ::Enumerator:



h = {foo: 0, bar: 1, baz: 2}
e = h.delete_if # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:delete_if>
e.each { |key, value| value > 0 } # => {:foo=>0}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2547



VALUE
rb_hash_delete_if(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    rb_hash_modify_check(hash);
    if (!RHASH_TABLE_EMPTY_P(hash)) {
        rb_hash_foreach(hash, delete_if_i, hash);
        compact_after_delete(hash);
    }
    return hash;
}


  








  

    #dig(key, *identifiers)  ⇒ Object   



  

    

Finds and returns the object in nested objects that is specified by #key and identifiers. The nested objects may be instances of various classes. See Dig Methods.



Nested Hashes:



h = {foo: {bar: {baz: 2}}}
h.dig(:foo) # => {:bar=>{:baz=>2}}
h.dig(:foo, :bar) # => {:baz=>2}
h.dig(:foo, :bar, :baz) # => 2
h.dig(:foo, :bar, :BAZ) # => nil



Nested Hashes and Arrays:



h = {foo: {bar: [:a, :b, :c]}}
h.dig(:foo, :bar, 2) # => :c



This method will use the default values for keys that are not present:



h = {foo: {bar: [:a, :b, :c]}}
h.dig(:hello) # => nil
h.default_proc = -> (hash, _key) { hash }
h.dig(:hello, :world) # => h
h.dig(:hello, :world, :foo, :bar, 2) # => :c


  



  [ GitHub ]


  

  


# File 'hash.c', line 4603



static VALUE
rb_hash_dig(int argc, VALUE *argv, VALUE self)
{
    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
    self = rb_hash_aref(self, *argv);
    if (!--argc) return self;
    ++argv;
    return rb_obj_dig(argc, argv, self, Qnil);
}


  








  

    

      #each {|key, value| ... } ⇒ self 
      #each_pair {|key, value| ... } ⇒ self 
      #each  ⇒ Enumerator 
      #each_pair  ⇒ Enumerator 
    

    Also known as: #each_pair
  



  

    

Calls the given block with each key-value pair; returns self:



h = {foo: 0, bar: 1, baz: 2}
h.each_pair {|key, value| puts "#{key}: #{value}"} # => {:foo=>0, :bar=>1, :baz=>2}



Output:



foo: 0
bar: 1
baz: 2



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.each_pair # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:each_pair>
h1 = e.each {|key, value| puts "#{key}: #{value}"}
h1 # => {:foo=>0, :bar=>1, :baz=>2}



Output:



foo: 0
bar: 1
baz: 2


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3132



static VALUE
rb_hash_each_pair(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    if (rb_block_pair_yield_optimizable())
        rb_hash_foreach(hash, each_pair_i_fast, 0);
    else
        rb_hash_foreach(hash, each_pair_i, 0);
    return hash;
}


  








  

    

      #each_key {|key| ... } ⇒ self 
      #each_key  ⇒ Enumerator 
    

  



  

    

Calls the given block with each key; returns self:



h = {foo: 0, bar: 1, baz: 2}
h.each_key {|key| puts key }  # => {:foo=>0, :bar=>1, :baz=>2}



Output:



foo
bar
baz



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.each_key # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:each_key>
h1 = e.each {|key| puts key }
h1 # => {:foo=>0, :bar=>1, :baz=>2}



Output:



foo
bar
baz


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3081



static VALUE
rb_hash_each_key(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    rb_hash_foreach(hash, each_key_i, 0);
    return hash;
}


  








  

    

      #each {|key, value| ... } ⇒ self 
      #each_pair {|key, value| ... } ⇒ self 
      #each  ⇒ Enumerator 
      #each_pair  ⇒ Enumerator 
    

  



  

    

Alias for #each.


  





  








  

    

      #each_value {|value| ... } ⇒ self 
      #each_value  ⇒ Enumerator 
    

  



  

    

Calls the given block with each value; returns self:



h = {foo: 0, bar: 1, baz: 2}
h.each_value {|value| puts value } # => {:foo=>0, :bar=>1, :baz=>2}



Output:



0
1
2



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.each_value # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:each_value>
h1 = e.each {|value| puts value }
h1 # => {:foo=>0, :bar=>1, :baz=>2}



Output:



0
1
2


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3043



static VALUE
rb_hash_each_value(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    rb_hash_foreach(hash, each_value_i, 0);
    return hash;
}


  








  

    #eql?(object)  ⇒ Boolean   



  

    

Returns true if all of the following are true:


  • 

    object is a Hash object.
    

  • 

    #hash and object have the same keys (regardless of order).
    

  • 

    For each key #key, h[key].eql?(object[key]).
    




Otherwise, returns false.



h1 = {foo: 0, bar: 1, baz: 2}
h2 = {foo: 0, bar: 1, baz: 2}
h1.eql? h2 # => true
h3 = {baz: 2, bar: 1, foo: 0}
h1.eql? h3 # => true


  



  [ GitHub ]


  

  


# File 'hash.c', line 3846



static VALUE
rb_hash_eql(VALUE hash1, VALUE hash2)
{
    return hash_equal(hash1, hash2, TRUE);
}


  








  

    #except(*keys)  ⇒ Hash   



  

    

Returns a new Hash excluding entries for the given #keys:



h = { a: 100, b: 200, c: 300 }
h.except(:a)          #=> {:b=>200, :c=>300}



Any given #keys that are not found are ignored.


  



  [ GitHub ]


  

  


# File 'hash.c', line 2666



static VALUE
rb_hash_except(int argc, VALUE *argv, VALUE hash)
{
    int i;
    VALUE key, result;

    result = hash_dup_with_compare_by_id(hash);

    for (i = 0; i < argc; i++) {
        key = argv[i];
        rb_hash_delete(result, key);
    }
    compact_after_delete(result);

    return result;
}


  








  

    

      #fetch(key)  ⇒ Object 
      #fetch(key, default_value)  ⇒ Object 
      #fetch(key) {|key| ... } ⇒ Object 
    

  



  

    

Returns the value for the given #key, if found.



h = {foo: 0, bar: 1, baz: 2}
h.fetch(:bar) # => 1



If #key is not found and no block was given, returns default_value:



{}.fetch(:nosuch, :default) # => :default



If #key is not found and a block was given, yields #key to the block and returns the block’s return value:



{}.fetch(:nosuch) {|key| "No key #{key}"} # => "No key nosuch"



Raises KeyError if neither default_value nor a block was given.



Note that this method does not use the values of either #default or #default_proc.


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2159



static VALUE
rb_hash_fetch_m(int argc, VALUE *argv, VALUE hash)
{
    VALUE key;
    st_data_t val;
    long block_given;

    rb_check_arity(argc, 1, 2);
    key = argv[0];

    block_given = rb_block_given_p();
    if (block_given && argc == 2) {
        rb_warn("block supersedes default value argument");
    }

    if (hash_stlike_lookup(hash, key, &val)) {
        return (VALUE)val;
    }
    else {
        if (block_given) {
            return rb_yield(key);
        }
        else if (argc == 1) {
            VALUE desc = rb_protect(rb_inspect, key, 0);
            if (NIL_P(desc)) {
                desc = rb_any_to_s(key);
            }
            desc = rb_str_ellipsize(desc, 65);
            rb_key_err_raise(rb_sprintf("key not found: %"PRIsVALUE, desc), hash, key);
        }
        else {
            return argv[1];
        }
    }
}


  








  

    

      #fetch_values(*keys)  ⇒ Array 
      #fetch_values(*keys) {|key| ... } ⇒ Array 
    

  



  

    

Returns a new ::Array containing the values associated with the given keys *keys:



h = {foo: 0, bar: 1, baz: 2}
h.fetch_values(:baz, :foo) # => [2, 0]



Returns a new empty ::Array if no arguments given.



When a block is given, calls the block with each missing key, treating the block’s return value as the value for that key:



h = {foo: 0, bar: 1, baz: 2}
values = h.fetch_values(:bar, :foo, :bad, :bam) {|key| key.to_s}
values # => [1, 0, "bad", "bam"]



When no block is given, raises an exception if any given key is not found.


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2728



static VALUE
rb_hash_fetch_values(int argc, VALUE *argv, VALUE hash)
{
    VALUE result = rb_ary_new2(argc);
    long i;

    for (i=0; i<argc; i++) {
        rb_ary_push(result, rb_hash_fetch(hash, argv[i]));
    }
    return result;
}


  








  

    

      #select {|key, value| ... } ⇒ Hash 
      #select  ⇒ Enumerator 
    

    Also known as: #select
  



  

    

Returns a new Hash object whose entries are those for which the block returns a truthy value:



h = {foo: 0, bar: 1, baz: 2}
h.select {|key, value| value < 2 } # => {:foo=>0, :bar=>1}



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.select # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:select>
e.each {|key, value| value < 2 } # => {:foo=>0, :bar=>1}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2765



static VALUE
rb_hash_select(VALUE hash)
{
    VALUE result;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    result = hash_dup_with_compare_by_id(hash);
    if (!RHASH_EMPTY_P(hash)) {
        rb_hash_foreach(result, keep_if_i, result);
        compact_after_delete(result);
    }
    return result;
}


  








  

    

      #select! {|key, value| ... } ⇒ self? 
      #select!  ⇒ Enumerator 
    

    Also known as: #select!
  



  

    

Returns self, whose entries are those for which the block returns a truthy value:



h = {foo: 0, bar: 1, baz: 2}
h.select! {|key, value| value < 2 }  => {:foo=>0, :bar=>1}



Returns nil if no entries were removed.



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.select!  # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:select!>
e.each { |key, value| value < 2 } # => {:foo=>0, :bar=>1}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2796



static VALUE
rb_hash_select_bang(VALUE hash)
{
    st_index_t n;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    rb_hash_modify_check(hash);
    n = RHASH_SIZE(hash);
    if (!n) return Qnil;
    rb_hash_foreach(hash, keep_if_i, hash);
    if (n == RHASH_SIZE(hash)) return Qnil;
    return hash;
}


  








  

    

      #flatten  ⇒ Array 
      #flatten(level)  ⇒ Array 
    

  



  

    

Returns a new ::Array object that is a 1-dimensional flattening of self.





By default, nested Arrays are not flattened:



h = {foo: 0, bar: [:bat, 3], baz: 2}
h.flatten # => [:foo, 0, :bar, [:bat, 3], :baz, 2]



Takes the depth of recursive flattening from ::Integer argument level:



h = {foo: 0, bar: [:bat, [:baz, [:bat, ]]]}
h.flatten(1) # => [:foo, 0, :bar, [:bat, [:baz, [:bat]]]]
h.flatten(2) # => [:foo, 0, :bar, :bat, [:baz, [:bat]]]
h.flatten(3) # => [:foo, 0, :bar, :bat, :baz, [:bat]]
h.flatten(4) # => [:foo, 0, :bar, :bat, :baz, :bat]



When level is negative, flattens all nested Arrays:



h = {foo: 0, bar: [:bat, [:baz, [:bat, ]]]}
h.flatten(-1) # => [:foo, 0, :bar, :bat, :baz, :bat]
h.flatten(-2) # => [:foo, 0, :bar, :bat, :baz, :bat]



When level is zero, returns the equivalent of #to_a :



h = {foo: 0, bar: [:bat, 3], baz: 2}
h.flatten(0) # => [[:foo, 0], [:bar, [:bat, 3]], [:baz, 2]]
h.flatten(0) == h.to_a # => true


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 4284



static VALUE
rb_hash_flatten(int argc, VALUE *argv, VALUE hash)
{
    VALUE ary;

    rb_check_arity(argc, 0, 1);

    if (argc) {
        int level = NUM2INT(argv[0]);

        if (level == 0) return rb_hash_to_a(hash);

        ary = rb_ary_new_capa(RHASH_SIZE(hash) * 2);
        rb_hash_foreach(hash, flatten_i, ary);
        level--;

        if (level > 0) {
            VALUE ary_flatten_level = INT2FIX(level);
            rb_funcallv(ary, id_flatten_bang, 1, &ary_flatten_level);
        }
        else if (level < 0) {
            /* flatten recursively */
            rb_funcallv(ary, id_flatten_bang, 0, 0);
        }
    }
    else {
        ary = rb_ary_new_capa(RHASH_SIZE(hash) * 2);
        rb_hash_foreach(hash, flatten_i, ary);
    }

    return ary;
}


  








  

    #freeze  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'hash.c', line 107



VALUE
rb_hash_freeze(VALUE hash)
{
    return rb_obj_freeze(hash);
}


  








  

    

      #include?(key)  ⇒ Boolean 
      #has_key?(key)  ⇒ Boolean 
      #key?(key)  ⇒ Boolean 
      #member?(key)  ⇒ Boolean 
    

  



  

    

Alias for #key?.


  





  








  

    

      #has_value?(value)  ⇒ Boolean 
      #value?(value)  ⇒ Boolean 
    

  



  

    

Alias for #value?.


  





  








  

    #hash  ⇒ Integer   



  

    

Returns the ::Integer hash-code for the hash.



Two Hash objects have the same hash-code if their content is the same (regardless of order):



h1 = {foo: 0, bar: 1, baz: 2}
h2 = {baz: 2, bar: 1, foo: 0}
h2.hash == h1.hash # => true
h2.eql? h1 # => true


  



  [ GitHub ]


  

  


# File 'hash.c', line 3878



static VALUE
rb_hash_hash(VALUE hash)
{
    st_index_t size = RHASH_SIZE(hash);
    st_index_t hval = rb_hash_start(size);
    hval = rb_hash_uint(hval, (st_index_t)rb_hash_hash);
    if (size) {
        rb_hash_foreach(hash, hash_i, (VALUE)&hval);
    }
    hval = rb_hash_end(hval);
    return ST2FIX(hval);
}


  








  

    

      #include?(key)  ⇒ Boolean 
      #has_key?(key)  ⇒ Boolean 
      #key?(key)  ⇒ Boolean 
      #member?(key)  ⇒ Boolean 
    

  



  

    

Alias for #key?.


  





  








  

    

      #replace(other_hash)  ⇒ self 
      #initialize_copy(other_hash)  ⇒ self 
    

  



  

    

Alias for #replace.


  





  








  

    

      #to_s  ⇒ String 
      #inspect  ⇒ String 
    

  



  

    

Alias for #to_s.


  





  








  

    #invert  ⇒ Hash   



  

    

Returns a new Hash object with the each key-value pair inverted:



h = {foo: 0, bar: 1, baz: 2}
h1 = h.invert
h1 # => {0=>:foo, 1=>:bar, 2=>:baz}



Overwrites any repeated new keys: (see Entry Order):



h = {foo: 0, bar: 0, baz: 0}
h.invert # => {0=>:baz}


  



  [ GitHub ]


  

  


# File 'hash.c', line 3913



static VALUE
rb_hash_invert(VALUE hash)
{
    VALUE h = rb_hash_new_with_size(RHASH_SIZE(hash));

    rb_hash_foreach(hash, rb_hash_invert_i, h);
    return h;
}


  








  

    

      #keep_if {|key, value| ... } ⇒ self 
      #keep_if  ⇒ Enumerator 
    

  



  

    

Calls the block for each key-value pair; retains the entry if the block returns a truthy value; otherwise deletes the entry; returns self.



h = {foo: 0, bar: 1, baz: 2}
h.keep_if { |key, value| key.start_with?('b') } # => {:bar=>1, :baz=>2}



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.keep_if # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:keep_if>
e.each { |key, value| key.start_with?('b') } # => {:bar=>1, :baz=>2}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2827



static VALUE
rb_hash_keep_if(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    rb_hash_modify_check(hash);
    if (!RHASH_TABLE_EMPTY_P(hash)) {
        rb_hash_foreach(hash, keep_if_i, hash);
    }
    return hash;
}


  








  

    #key(value)  ⇒ key?   



  

    

Returns the key for the first-found entry with the given value (see Entry Order):



h = {foo: 0, bar: 2, baz: 2}
h.key(0) # => :foo
h.key(2) # => :bar



Returns nil if no such value is found.


  



  [ GitHub ]


  

  


# File 'hash.c', line 2337



static VALUE
rb_hash_key(VALUE hash, VALUE value)
{
    VALUE args[2];

    args[0] = value;
    args[1] = Qnil;

    rb_hash_foreach(hash, key_i, (VALUE)args);

    return args[1];
}


  








  

    

      #include?(key)  ⇒ Boolean 
      #has_key?(key)  ⇒ Boolean 
      #key?(key)  ⇒ Boolean 
      #member?(key)  ⇒ Boolean 
    

    Also known as: #include?, #member?, #has_key?
  



  

    

Returns true if #key is a key in self, otherwise false.


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3685



VALUE
rb_hash_has_key(VALUE hash, VALUE key)
{
    return RBOOL(hash_stlike_lookup(hash, key, NULL));
}


  








  

    #keys  ⇒ Array   



  

    

Returns a new ::Array containing all keys in self:



h = {foo: 0, bar: 1, baz: 2}
h.keys # => [:foo, :bar, :baz]


  



  [ GitHub ]


  

  


# File 'hash.c', line 3598



VALUE
rb_hash_keys(VALUE hash)
{
    st_index_t size = RHASH_SIZE(hash);
    VALUE keys =  rb_ary_new_capa(size);

    if (size == 0) return keys;

    if (ST_DATA_COMPATIBLE_P(VALUE)) {
        RARRAY_PTR_USE(keys, ptr, {
            if (RHASH_AR_TABLE_P(hash)) {
                size = ar_keys(hash, ptr, size);
            }
            else {
                st_table *table = RHASH_ST_TABLE(hash);
                size = st_keys(table, ptr, size);
            }
        });
        rb_gc_writebarrier_remember(keys);
        rb_ary_set_len(keys, size);
    }
    else {
        rb_hash_foreach(hash, keys_i, keys);
    }

    return keys;
}


  








  

    

      #length  ⇒ Integer 
      #size  ⇒ Integer 
    

    Also known as: #size
  



  

    

Returns the count of entries in self:



{foo: 0, bar: 1, baz: 2}.length # => 3


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2985



VALUE
rb_hash_size(VALUE hash)
{
    return INT2FIX(RHASH_SIZE(hash));
}


  








  

    

      #include?(key)  ⇒ Boolean 
      #has_key?(key)  ⇒ Boolean 
      #key?(key)  ⇒ Boolean 
      #member?(key)  ⇒ Boolean 
    

  



  

    

Alias for #key?.


  





  








  

    

      #merge  ⇒ copy_of_self 
      #merge(*other_hashes)  ⇒ Hash 
      #merge(*other_hashes) {|key, old_value, new_value| ... } ⇒ Hash 
    

  



  

    

Returns the new Hash formed by merging each of other_hashes into a copy of self.



Each argument in other_hashes must be a Hash.





With arguments and no block:


  • 

    Returns the new Hash object formed by merging each successive Hash in other_hashes into self.
    

  • 

    Each new-key entry is added at the end.
    

  • 

    Each duplicate-key entry’s value overwrites the previous value.
    




Example:



h = {foo: 0, bar: 1, baz: 2}
h1 = {bat: 3, bar: 4}
h2 = {bam: 5, bat:6}
h.merge(h1, h2) # => {:foo=>0, :bar=>4, :baz=>2, :bat=>6, :bam=>5}



With arguments and a block:


  • 

    Returns a new Hash object that is the merge of self and each given hash.
    

  • 

    The given hashes are merged left to right.
    

  • 

    Each new-key entry is added at the end.
    

  • 

    For each duplicate key:
    

    • 

      Calls the block with the key and the old and new values.
      

    • 

      The block’s return value becomes the new value for the entry.
      

    




Example:



h = {foo: 0, bar: 1, baz: 2}
h1 = {bat: 3, bar: 4}
h2 = {bam: 5, bat:6}
h3 = h.merge(h1, h2) { |key, old_value, new_value| old_value + new_value }
h3 # => {:foo=>0, :bar=>5, :baz=>2, :bat=>9, :bam=>5}



With no arguments:


  • 

    Returns a copy of self.
    

  • 

    The block, if given, is ignored.
    




Example:



h = {foo: 0, bar: 1, baz: 2}
h.merge # => {:foo=>0, :bar=>1, :baz=>2}
h1 = h.merge { |key, old_value, new_value| raise 'Cannot happen' }
h1 # => {:foo=>0, :bar=>1, :baz=>2}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 4120



static VALUE
rb_hash_merge(int argc, VALUE *argv, VALUE self)
{
    return rb_hash_update(argc, argv, copy_compare_by_id(rb_hash_dup(self), self));
}


  








  

    

      #merge!  ⇒ self 
      #merge!(*other_hashes)  ⇒ self 
      #merge!(*other_hashes) {|key, old_value, new_value| ... } ⇒ self 
    

    Also known as: #update
  



  

    

Merges each of other_hashes into self; returns self.



Each argument in other_hashes must be a Hash.



With arguments and no block:


  • 

    Returns self, after the given hashes are merged into it.
    

  • 

    The given hashes are merged left to right.
    

  • 

    Each new entry is added at the end.
    

  • 

    Each duplicate-key entry’s value overwrites the previous value.
    




Example:



h = {foo: 0, bar: 1, baz: 2}
h1 = {bat: 3, bar: 4}
h2 = {bam: 5, bat:6}
h.merge!(h1, h2) # => {:foo=>0, :bar=>4, :baz=>2, :bat=>6, :bam=>5}



With arguments and a block:


  • 

    Returns self, after the given hashes are merged.
    

  • 

    The given hashes are merged left to right.
    

  • 

    Each new-key entry is added at the end.
    

  • 

    For each duplicate key:
    

    • 

      Calls the block with the key and the old and new values.
      

    • 

      The block’s return value becomes the new value for the entry.
      

    




Example:



h = {foo: 0, bar: 1, baz: 2}
h1 = {bat: 3, bar: 4}
h2 = {bam: 5, bat:6}
h3 = h.merge!(h1, h2) { |key, old_value, new_value| old_value + new_value }
h3 # => {:foo=>0, :bar=>5, :baz=>2, :bat=>9, :bam=>5}



With no arguments:


  • 

    Returns self, unmodified.
    

  • 

    The block, if given, is ignored.
    




Example:



h = {foo: 0, bar: 1, baz: 2}
h.merge # => {:foo=>0, :bar=>1, :baz=>2}
h1 = h.merge! { |key, old_value, new_value| raise 'Cannot happen' }
h1 # => {:foo=>0, :bar=>1, :baz=>2}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 4001



static VALUE
rb_hash_update(int argc, VALUE *argv, VALUE self)
{
    int i;
    bool block_given = rb_block_given_p();

    rb_hash_modify(self);
    for (i = 0; i < argc; i++){
        VALUE hash = to_hash(argv[i]);
        if (block_given) {
            rb_hash_foreach(hash, rb_hash_update_block_i, self);
        }
        else {
            rb_hash_foreach(hash, rb_hash_update_i, self);
        }
    }
    return self;
}


  








  

    #rassoc(value)  ⇒ Array?   



  

    

Returns a new 2-element ::Array consisting of the key and value of the first-found entry whose value is #== to value (see Entry Order):



h = {foo: 0, bar: 1, baz: 1}
h.rassoc(1) # => [:bar, 1]



Returns nil if no such value found.


  



  [ GitHub ]


  

  


# File 'hash.c', line 4230



static VALUE
rb_hash_rassoc(VALUE hash, VALUE obj)
{
    VALUE args[2];

    args[0] = obj;
    args[1] = Qnil;
    rb_hash_foreach(hash, rassoc_i, (VALUE)args);
    return args[1];
}


  








  

    #rehash  ⇒ self   



  

    

Rebuilds the hash table by recomputing the hash index for each key; returns self.



The hash table becomes invalid if the hash value of a key has changed after the entry was created. See Modifying an Active Hash Key.


  



  [ GitHub ]


  

  


# File 'hash.c', line 1998



VALUE
rb_hash_rehash(VALUE hash)
{
    VALUE tmp;
    st_table *tbl;

    if (hash_iterating_p(hash)) {
        rb_raise(rb_eRuntimeError, "rehash during iteration");
    }
    rb_hash_modify_check(hash);
    if (RHASH_AR_TABLE_P(hash)) {
        tmp = hash_alloc(0);
        rb_hash_foreach(hash, rb_hash_rehash_i, (VALUE)tmp);

        hash_ar_free_and_clear_table(hash);
        ar_copy(hash, tmp);
    }
    else if (RHASH_ST_TABLE_P(hash)) {
        st_table *old_tab = RHASH_ST_TABLE(hash);
        tmp = hash_alloc(0);

        hash_st_table_init(tmp, old_tab->type, old_tab->num_entries);
        tbl = RHASH_ST_TABLE(tmp);

        rb_hash_foreach(hash, rb_hash_rehash_i, (VALUE)tmp);

        hash_st_free(hash);
        RHASH_ST_TABLE_SET(hash, tbl);
        RHASH_ST_CLEAR(tmp);
    }
    hash_verify(hash);
    return hash;
}


  








  

    

      #reject {|key, value| ... } ⇒ Hash 
      #reject  ⇒ Enumerator 
    

  



  

    

Returns a new Hash object whose entries are all those from self for which the block returns false or nil:



h = {foo: 0, bar: 1, baz: 2}
h1 = h.reject {|key, value| key.start_with?('b') }
h1 # => {:foo=>0}



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.reject # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:reject>
h1 = e.each {|key, value| key.start_with?('b') }
h1 # => {:foo=>0}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2609



static VALUE
rb_hash_reject(VALUE hash)
{
    VALUE result;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    result = hash_dup_with_compare_by_id(hash);
    if (!RHASH_EMPTY_P(hash)) {
        rb_hash_foreach(result, delete_if_i, result);
        compact_after_delete(result);
    }
    return result;
}


  








  

    

      #reject! {|key, value| ... } ⇒ self? 
      #reject!  ⇒ Enumerator 
    

  



  

    

Returns self, whose remaining entries are those for which the block returns false or nil:



h = {foo: 0, bar: 1, baz: 2}
h.reject! {|key, value| value < 2 } # => {:baz=>2}



Returns nil if no entries are removed.



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.reject! # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:reject!>
e.each {|key, value| key.start_with?('b') } # => {:foo=>0}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 2577



static VALUE
rb_hash_reject_bang(VALUE hash)
{
    st_index_t n;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    rb_hash_modify(hash);
    n = RHASH_SIZE(hash);
    if (!n) return Qnil;
    rb_hash_foreach(hash, delete_if_i, hash);
    if (n == RHASH_SIZE(hash)) return Qnil;
    return hash;
}


  








  

    #replace(other_hash)  ⇒ self     Also known as: #initialize_copy
  



  

    

Replaces the entire contents of self with the contents of other_hash; returns self:



h = {foo: 0, bar: 1, baz: 2}
h.replace({bat: 3, bam: 4}) # => {:bat=>3, :bam=>4}


  



  [ GitHub ]


  

  


# File 'hash.c', line 2950



static VALUE
rb_hash_replace(VALUE hash, VALUE hash2)
{
    rb_hash_modify_check(hash);
    if (hash == hash2) return hash;
    if (hash_iterating_p(hash)) {
        rb_raise(rb_eRuntimeError, "can't replace hash during iteration");
    }
    hash2 = to_hash(hash2);

    COPY_DEFAULT(hash, hash2);

    if (RHASH_AR_TABLE_P(hash)) {
        hash_ar_free_and_clear_table(hash);
    }
    else {
        hash_st_free_and_clear_table(hash);
    }

    hash_copy(hash, hash2);

    return hash;
}


  








  

    

      #select {|key, value| ... } ⇒ Hash 
      #select  ⇒ Enumerator 
    

  



  

    

Alias for #filter.


  





  








  

    

      #select! {|key, value| ... } ⇒ self? 
      #select!  ⇒ Enumerator 
    

  



  

    

Alias for #filter!.


  





  








  

    #shift  ⇒ Array, value   



  

    

Removes the first hash entry (see Entry Order); returns a 2-element ::Array containing the removed key and value:



h = {foo: 0, bar: 1, baz: 2}
h.shift # => [:foo, 0]
h # => {:bar=>1, :baz=>2}



Returns nil if the hash is empty.


  



  [ GitHub ]


  

  


# File 'hash.c', line 2475



static VALUE
rb_hash_shift(VALUE hash)
{
    struct shift_var var;

    rb_hash_modify_check(hash);
    if (RHASH_AR_TABLE_P(hash)) {
        var.key = Qundef;
        if (!hash_iterating_p(hash)) {
            if (ar_shift(hash, &var.key, &var.val)) {
                return rb_assoc_new(var.key, var.val);
            }
        }
        else {
            rb_hash_foreach(hash, shift_i_safe, (VALUE)&var);
            if (!UNDEF_P(var.key)) {
                rb_hash_delete_entry(hash, var.key);
                return rb_assoc_new(var.key, var.val);
            }
        }
    }
    if (RHASH_ST_TABLE_P(hash)) {
        var.key = Qundef;
        if (!hash_iterating_p(hash)) {
            if (st_shift(RHASH_ST_TABLE(hash), &var.key, &var.val)) {
                return rb_assoc_new(var.key, var.val);
            }
        }
        else {
            rb_hash_foreach(hash, shift_i_safe, (VALUE)&var);
            if (!UNDEF_P(var.key)) {
                rb_hash_delete_entry(hash, var.key);
                return rb_assoc_new(var.key, var.val);
            }
        }
    }
    return Qnil;
}


  








  

    

      #length  ⇒ Integer 
      #size  ⇒ Integer 
    

  



  

    

Alias for #length.


  





  








  

    #slice(*keys)  ⇒ Hash   



  

    

Returns a new Hash object containing the entries for the given #keys:



h = {foo: 0, bar: 1, baz: 2}
h.slice(:baz, :foo) # => {:baz=>2, :foo=>0}



Any given #keys that are not found are ignored.


  



  [ GitHub ]


  

  


# File 'hash.c', line 2634



static VALUE
rb_hash_slice(int argc, VALUE *argv, VALUE hash)
{
    int i;
    VALUE key, value, result;

    if (argc == 0 || RHASH_EMPTY_P(hash)) {
        return copy_compare_by_id(rb_hash_new(), hash);
    }
    result = copy_compare_by_id(rb_hash_new_with_size(argc), hash);

    for (i = 0; i < argc; i++) {
        key = argv[i];
        value = rb_hash_lookup2(hash, key, Qundef);
        if (!UNDEF_P(value))
            rb_hash_aset(result, key, value);
    }

    return result;
}


  








  

    

      #[]=(key, value)  ⇒ value 
      #store(key, value)  
    

  



  

    

Alias for #[]=.


  





  








  

    #to_a  ⇒ Array   



  

    

Returns a new ::Array of 2-element ::Array objects; each nested ::Array contains a key-value pair from self:



h = {foo: 0, bar: 1, baz: 2}
h.to_a # => [[:foo, 0], [:bar, 1], [:baz, 2]]


  



  [ GitHub ]


  

  


# File 'hash.c', line 3397



static VALUE
rb_hash_to_a(VALUE hash)
{
    VALUE ary;

    ary = rb_ary_new_capa(RHASH_SIZE(hash));
    rb_hash_foreach(hash, to_a_i, ary);

    return ary;
}


  








  

    

      #to_h  ⇒ self, Hash 
      #to_h {|key, value| ... } ⇒ Hash 
    

  



  

    

For an instance of Hash, returns self.



For a subclass of Hash, returns a new Hash containing the content of self.



When a block is given, returns a new Hash object whose content is based on the block; the block should return a 2-element ::Array object specifying the key-value pair to be included in the returned ::Array:



h = {foo: 0, bar: 1, baz: 2}
h1 = h.to_h {|key, value| [value, key] }
h1 # => {0=>:foo, 1=>:bar, 2=>:baz}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3569



static VALUE
rb_hash_to_h(VALUE hash)
{
    if (rb_block_given_p()) {
        return rb_hash_to_h_block(hash);
    }
    if (rb_obj_class(hash) != rb_cHash) {
        const VALUE flags = RBASIC(hash)->flags;
        hash = hash_dup(hash, rb_cHash, flags & RHASH_PROC_DEFAULT);
    }
    return hash;
}


  








  

    #to_hash  ⇒ self   



  

    

Returns self.


  



  [ GitHub ]


  

  


# File 'hash.c', line 3511



static VALUE
rb_hash_to_hash(VALUE hash)
{
    return hash;
}


  








  

    #to_proc  ⇒ Proc   



  

    

Returns a ::Proc object that maps a key to its value:



h = {foo: 0, bar: 1, baz: 2}
proc = h.to_proc
proc.class # => Proc
proc.call(:foo) # => 0
proc.call(:bar) # => 1
proc.call(:nosuch) # => nil


  



  [ GitHub ]


  

  


# File 'hash.c', line 4728



static VALUE
rb_hash_to_proc(VALUE hash)
{
    return rb_func_lambda_new(hash_proc_call, hash, 1, 1);
}


  








  

    #to_s  ⇒ String     Also known as: #inspect
  



  

    

Returns a new ::String containing the hash entries:



h = {foo: 0, bar: 1, baz: 2}
h.inspect # => "{:foo=>0, :bar=>1, :baz=>2}"


  



  [ GitHub ]


  

  


# File 'hash.c', line 3497



static VALUE
rb_hash_inspect(VALUE hash)
{
    if (RHASH_EMPTY_P(hash))
        return rb_usascii_str_new2("{}");
    return rb_exec_recursive(inspect_hash, hash, 0);
}


  








  

    

      #transform_keys {|key| ... } ⇒ Hash 
      #transform_keys(hash2)  ⇒ Hash 
      #transform_keys(hash2) {|other_key| ... } ⇒ Hash 
      #transform_keys  ⇒ Enumerator 
    

  



  

    

Returns a new Hash object; each entry has:


  • 

    A key provided by the block.
    

  • 

    The value from self.
    




An optional hash argument can be provided to map keys to new keys. Any key not given will be mapped using the provided block, or remain the same if no block is given.



Transform keys:



h = {foo: 0, bar: 1, baz: 2}
h1 = h.transform_keys {|key| key.to_s }
h1 # => {"foo"=>0, "bar"=>1, "baz"=>2}

h.transform_keys(foo: :bar, bar: :foo)
#=> {bar: 0, foo: 1, baz: 2}

h.transform_keys(foo: :hello, &:to_s)
#=> {:hello=>0, "bar"=>1, "baz"=>2}



Overwrites values for duplicate keys:



h = {foo: 0, bar: 1, baz: 2}
h1 = h.transform_keys {|key| :bat }
h1 # => {:bat=>2}



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.transform_keys # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:transform_keys>
h1 = e.each { |key| key.to_s }
h1 # => {"foo"=>0, "bar"=>1, "baz"=>2}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3210



static VALUE
rb_hash_transform_keys(int argc, VALUE *argv, VALUE hash)
{
    VALUE result;
    struct transform_keys_args transarg = {0};

    argc = rb_check_arity(argc, 0, 1);
    if (argc > 0) {
        transarg.trans = to_hash(argv[0]);
        transarg.block_given = rb_block_given_p();
    }
    else {
        RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    }
    result = rb_hash_new();
    if (!RHASH_EMPTY_P(hash)) {
        if (transarg.trans) {
            transarg.result = result;
            rb_hash_foreach(hash, transform_keys_hash_i, (VALUE)&transarg);
        }
        else {
            rb_hash_foreach(hash, transform_keys_i, result);
        }
    }

    return result;
}


  








  

    

      #transform_keys! {|key| ... } ⇒ self 
      #transform_keys!(hash2)  ⇒ self 
      #transform_keys!(hash2) {|other_key| ... } ⇒ self 
      #transform_keys!  ⇒ Enumerator 
    

  



  

    

Same as #transform_keys but modifies the receiver in place instead of returning a new hash.


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3250



static VALUE
rb_hash_transform_keys_bang(int argc, VALUE *argv, VALUE hash)
{
    VALUE trans = 0;
    int block_given = 0;

    argc = rb_check_arity(argc, 0, 1);
    if (argc > 0) {
        trans = to_hash(argv[0]);
        block_given = rb_block_given_p();
    }
    else {
        RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    }
    rb_hash_modify_check(hash);
    if (!RHASH_TABLE_EMPTY_P(hash)) {
        long i;
        VALUE new_keys = hash_alloc(0);
        VALUE pairs = rb_ary_hidden_new(RHASH_SIZE(hash) * 2);
        rb_hash_foreach(hash, flatten_i, pairs);
        for (i = 0; i < RARRAY_LEN(pairs); i += 2) {
            VALUE key = RARRAY_AREF(pairs, i), new_key, val;

            if (!trans) {
                new_key = rb_yield(key);
            }
            else if (!UNDEF_P(new_key = rb_hash_lookup2(trans, key, Qundef))) {
                /* use the transformed key */
            }
            else if (block_given) {
                new_key = rb_yield(key);
            }
            else {
                new_key = key;
            }
            val = RARRAY_AREF(pairs, i+1);
            if (!hash_stlike_lookup(new_keys, key, NULL)) {
                rb_hash_stlike_delete(hash, &key, NULL);
            }
            rb_hash_aset(hash, new_key, val);
            rb_hash_aset(new_keys, new_key, Qnil);
        }
        rb_ary_clear(pairs);
        rb_hash_clear(new_keys);
    }
    compact_after_delete(hash);
    return hash;
}


  








  

    

      #transform_values {|value| ... } ⇒ Hash 
      #transform_values  ⇒ Enumerator 
    

  



  

    

Returns a new Hash object; each entry has:


  • 

    A key from self.
    

  • 

    A value provided by the block.
    




Transform values:



h = {foo: 0, bar: 1, baz: 2}
h1 = h.transform_values {|value| value * 100}
h1 # => {:foo=>0, :bar=>100, :baz=>200}



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.transform_values # => #<Enumerator: {:foo=>0, :bar=>1, :baz=>2}:transform_values>
h1 = e.each { |value| value * 100}
h1 # => {:foo=>0, :bar=>100, :baz=>200}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3335



static VALUE
rb_hash_transform_values(VALUE hash)
{
    VALUE result;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    result = hash_dup_with_compare_by_id(hash);
    SET_DEFAULT(result, Qnil);

    if (!RHASH_EMPTY_P(hash)) {
        rb_hash_stlike_foreach_with_replace(result, transform_values_foreach_func, transform_values_foreach_replace, result);
        compact_after_delete(result);
    }

    return result;
}


  








  

    

      #transform_values! {|value| ... } ⇒ self 
      #transform_values!  ⇒ Enumerator 
    

  



  

    

Returns self, whose keys are unchanged, and whose values are determined by the given block.



h = {foo: 0, bar: 1, baz: 2}
h.transform_values! {|value| value * 100} # => {:foo=>0, :bar=>100, :baz=>200}



Returns a new ::Enumerator if no block given:



h = {foo: 0, bar: 1, baz: 2}
e = h.transform_values! # => #<Enumerator: {:foo=>0, :bar=>100, :baz=>200}:transform_values!>
h1 = e.each {|value| value * 100}
h1 # => {:foo=>0, :bar=>100, :baz=>200}


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3367



static VALUE
rb_hash_transform_values_bang(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
    rb_hash_modify_check(hash);

    if (!RHASH_TABLE_EMPTY_P(hash)) {
        rb_hash_stlike_foreach_with_replace(hash, transform_values_foreach_func, transform_values_foreach_replace, hash);
    }

    return hash;
}


  








  

    

      #merge!  ⇒ self 
      #merge!(*other_hashes)  ⇒ self 
      #merge!(*other_hashes) {|key, old_value, new_value| ... } ⇒ self 
    

  



  

    

Alias for #merge!.


  





  








  

    

      #has_value?(value)  ⇒ Boolean 
      #value?(value)  ⇒ Boolean 
    

    Also known as: #has_value?
  



  

    

Returns true if value is a value in self, otherwise false.


  





  


  [ GitHub ]


  

  


# File 'hash.c', line 3711



static VALUE
rb_hash_has_value(VALUE hash, VALUE val)
{
    VALUE data[2];

    data[0] = Qfalse;
    data[1] = val;
    rb_hash_foreach(hash, rb_hash_search_value, (VALUE)data);
    return data[0];
}


  








  

    #values  ⇒ Array   



  

    

Returns a new ::Array containing all values in self:



h = {foo: 0, bar: 1, baz: 2}
h.values # => [0, 1, 2]


  



  [ GitHub ]


  

  


# File 'hash.c', line 3642



VALUE
rb_hash_values(VALUE hash)
{
    VALUE values;
    st_index_t size = RHASH_SIZE(hash);

    values = rb_ary_new_capa(size);
    if (size == 0) return values;

    if (ST_DATA_COMPATIBLE_P(VALUE)) {
        if (RHASH_AR_TABLE_P(hash)) {
            rb_gc_writebarrier_remember(values);
            RARRAY_PTR_USE(values, ptr, {
                size = ar_values(hash, ptr, size);
            });
        }
        else if (RHASH_ST_TABLE_P(hash)) {
            st_table *table = RHASH_ST_TABLE(hash);
            rb_gc_writebarrier_remember(values);
            RARRAY_PTR_USE(values, ptr, {
                size = st_values(table, ptr, size);
            });
        }
        rb_ary_set_len(values, size);
    }

    else {
        rb_hash_foreach(hash, values_i, values);
    }

    return values;
}


  








  

    #values_at(*keys)  ⇒ Array   



  

    

Returns a new ::Array containing values for the given #keys:



h = {foo: 0, bar: 1, baz: 2}
h.values_at(:baz, :foo) # => [2, 0]



The default values are returned for any keys that are not found:



h.values_at(:hello, :foo) # => [nil, 0]


  



  [ GitHub ]


  

  


# File 'hash.c', line 2696



static VALUE
rb_hash_values_at(int argc, VALUE *argv, VALUE hash)
{
    VALUE result = rb_ary_new2(argc);
    long i;

    for (i=0; i<argc; i++) {
        rb_ary_push(result, rb_hash_aref(hash, argv[i]));
    }
    return result;
}