Class: ActiveSupport::HashWithIndifferentAccess

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses: ActionController::Parameters
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, ::Hash
Instance Chain: self, ::Hash
Inherits:	Hash ::Object Hash ActiveSupport::HashWithIndifferentAccess
Defined in:	activesupport/lib/active_support/hash_with_indifferent_access.rb

Overview

Implements a hash where keys :foo and "foo" are considered to be the same.

rgb = ActiveSupport::HashWithIndifferentAccess.new

rgb[:black] = '#000000'
rgb[:black]  # => '#000000'
rgb['black'] # => '#000000'

rgb['white'] = '#FFFFFF'
rgb[:white]  # => '#FFFFFF'
rgb['white'] # => '#FFFFFF'

Internally symbols are mapped to strings when used as keys in the entire writing interface (calling #[]=, #merge, etc). This mapping belongs to the public interface. For example, given:

hash = ActiveSupport::HashWithIndifferentAccess.new(a: 1)

You are guaranteed that the key is returned as a string:

hash.keys # => ["a"]

Technically other types of keys are accepted:

hash = ActiveSupport::HashWithIndifferentAccess.new(a: 1)
hash[0] = 0
hash # => {"a"=>1, 0=>0}

but this class is intended for use cases where strings or symbols are the expected keys and it is convenient to understand both as the same. For example the params hash in Ruby on ::Rails.

Note that core extensions define Hash#with_indifferent_access:

rgb = { black: '#000000', white: '#FFFFFF' }.with_indifferent_access

which may be handy.

Class Method Summary

.[](*args)
.new(constructor = {}) ⇒ HashWithIndifferentAccess constructor
.new_from_hash_copying_default(hash)

::Hash - Inherited

.from_trusted_xml	Builds a ::Hash from XML just like Hash.from_xml, but also allows ::Symbol and YAML.
.from_xml	Returns a ::Hash containing a collection of pairs when the key is the node name and the value is its content.

Instance Attribute Summary

#extractable_options? ⇒ Boolean readonly

Returns true so that Array#extract_options! finds members of this class.

::Hash - Inherited

#extractable_options?

By default, only instances of ::Hash itself are extractable.

Instance Method Summary

#[]=(key, value) (also: #store)

Assigns a new value to the hash:
#compact
#deep_stringify_keys
#deep_stringify_keys!
#deep_symbolize_keys
#default(key = nil)
#delete(key)

Removes the specified key from the hash.
#dup

Returns a shallow copy of the hash.
#fetch(key, *extras)

Same as Hash#fetch where the key passed as argument can be either a string or a symbol:
#has_key?(key)

Alias for #key?.
#include?(key)

Alias for #key?.
#key?(key) ⇒ Boolean (also: #include?, #has_key?, #member?)

Checks the hash for a key matching the argument passed in:
#member?(key)

Alias for #key?.
#merge(hash, &block)

This method has the same semantics of #update, except it does not modify the receiver but rather returns a new hash with indifferent access with the result of the merge.
#merge!(other_hash)

Alias for #update.
#nested_under_indifferent_access
#regular_update
#regular_writer
#reject(*args, &block)
#replace(other_hash)

Replaces the contents of this hash with other_hash.
#reverse_merge(other_hash)

Like #merge but the other way around: Merges the receiver into the argument and returns a new hash with indifferent access as result:
#reverse_merge!(other_hash)

Same semantics as #reverse_merge but modifies the receiver in-place.
#select(*args, &block)
#store(key, value)

Alias for #[]=.
#stringify_keys
#stringify_keys!
#symbolize_keys
#to_hash

Convert to a regular hash with string keys.
#to_options!
#transform_values(*args, &block)
#update(other_hash) (also: #merge!)

Updates the receiver in-place, merging in the hash passed as argument:
#values_at(*indices)

Returns an array of the values at the specified indices:
#with_indifferent_access

::Hash - Inherited

#assert_valid_keys	Validate all keys in a hash match `*valid_keys`, raising ArgumentError on a mismatch.
#blank?	A hash is blank if it's empty:
#compact	Returns a hash with non `nil` values.
#compact!	Replaces current hash with non `nil` values.
#deep_dup	Returns a deep copy of hash.
#deep_merge	Returns a new hash with `self` and `other_hash` merged recursively.
#deep_merge!	Same as `deep_merge`, but modifies `self`.
#deep_stringify_keys	Returns a new hash with all keys converted to strings.
#deep_stringify_keys!	Destructively convert all keys to strings.
#deep_symbolize_keys	Returns a new hash with all keys converted to symbols, as long as they respond to `to_sym`.
#deep_symbolize_keys!	Destructively convert all keys to symbols, as long as they respond to `to_sym`.
#deep_transform_keys	Returns a new hash with all keys converted by the block operation.
#deep_transform_keys!	Destructively convert all keys by using the block operation.
#except	Returns a hash that includes everything but the given keys.
#except!	Replaces the hash without the given keys.
#extract!	Removes and returns the key/value pairs matching the given keys.
#nested_under_indifferent_access	Alias for Hash#with_indifferent_access.
#reverse_merge	Merges the caller into `other_hash`.
#reverse_merge!	Destructive #reverse_merge.
#reverse_update	Alias for Hash#reverse_merge!.
#slice	Slice a hash to include only the given keys.
#slice!	Replaces the hash with only the given keys.
#stringify_keys	Returns a new hash with all keys converted to strings.
#stringify_keys!	Destructively convert all keys to strings.
#symbolize_keys	Returns a new hash with all keys converted to symbols, as long as they respond to `to_sym`.
#symbolize_keys!	Destructively convert all keys to symbols, as long as they respond to `to_sym`.
#to_options	Alias for Hash#symbolize_keys.
#to_options!	Alias for Hash#symbolize_keys!.
#to_param	Alias for Hash#to_query.
#to_query	Returns a string representation of the receiver suitable for use as a URL query string:
#to_xml	Returns a string containing an XML representation of its receiver:
#transform_keys	Returns a new hash with all keys converted using the block operation.
#transform_keys!	Destructively convert all keys using the block operations.
#transform_values	Returns a new hash with the results of running `block` once for every value.
#transform_values!	Destructive #transform_values
#with_indifferent_access	Returns an `HashWithIndifferentAccess` out of its receiver:

Constructor Details

.new(constructor = {}) ⇒ `HashWithIndifferentAccess`

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 58


def initialize(constructor = {})
  if constructor.respond_to?(:to_hash)
    super()
    update(constructor)
  else
    super(constructor)
  end
end

Class Method Details

.[](*args)

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 83


def self.[](*args)
  new.merge!(Hash[*args])
end

.new_from_hash_copying_default(hash)

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 75


def self.new_from_hash_copying_default(hash)
  hash = hash.to_hash
  new(hash).tap do |new_hash|
    new_hash.default = hash.default
    new_hash.default_proc = hash.default_proc if hash.default_proc
  end
end

Instance Attribute Details

#extractable_options? ⇒ `Boolean` (readonly)

Returns true so that Array#extract_options! finds members of this class.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 46


def extractable_options?
  true
end

Instance Method Details

#[]=(key, value) Also known as: #store

Assigns a new value to the hash:

hash = ActiveSupport::HashWithIndifferentAccess.new
hash[:key] = 'value'

This value can be later fetched using either :key or 'key'.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 96


def []=(key, value)
  regular_writer(convert_key(key), convert_value(value, for: :assignment))
end

#compact

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 253


def compact
  dup.tap(&:compact!)
end

#deep_stringify_keys

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 233


def deep_stringify_keys; dup end

#deep_stringify_keys!

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 231


def deep_stringify_keys!; self end

#deep_symbolize_keys

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 237


def deep_symbolize_keys; to_hash.deep_symbolize_keys! end

#default(key = nil)

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 67


def default(key = nil)
  if key.is_a?(Symbol) && include?(key = key.to_s)
    self[key]
  else
    super
  end
end

#delete(key)

Removes the specified key from the hash.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 226


def delete(key)
  super(convert_key(key))
end

#dup

Returns a shallow copy of the hash.

hash = ActiveSupport::HashWithIndifferentAccess.new({ a: { b: 'b' } })
dup  = hash.dup
dup[:a][:c] = 'c'

hash[:a][:c] # => nil
dup[:a][:c]  # => "c"

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 189


def dup
  self.class.new(self).tap do |new_hash|
    set_defaults(new_hash)
  end
end

#fetch(key, *extras)

Same as Hash#fetch where the key passed as argument can be either a string or a symbol:

counters = ActiveSupport::HashWithIndifferentAccess.new
counters[:foo] = 1

counters.fetch('foo')          # => 1
counters.fetch(:bar, 0)        # => 0
counters.fetch(:bar) { |key| 0 } # => 0
counters.fetch(:zoo)           # => KeyError: key not found: "zoo"

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 167


def fetch(key, *extras)
  super(convert_key(key), *extras)
end

#has_key?(key)

Alias for #key?.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 154


alias_method :has_key?, :key?

#include?(key)

Alias for #key?.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 153


alias_method :include?, :key?

#key?(key) ⇒ `Boolean` Also known as: #include?, #has_key?, #member?

Checks the hash for a key matching the argument passed in:

hash = ActiveSupport::HashWithIndifferentAccess.new
hash['key'] = 'value'
hash.key?(:key)  # => true
hash.key?('key') # => true

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 149


def key?(key)
  super(convert_key(key))
end

#member?(key)

Alias for #key?.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 155


alias_method :member?, :key?

#merge(hash, &block)

This method has the same semantics of #update, except it does not modify the receiver but rather returns a new hash with indifferent access with the result of the merge.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 198


def merge(hash, &block)
  self.dup.update(hash, &block)
end

#merge!(other_hash)

Alias for #update.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 141


alias_method :merge!, :update

#nested_under_indifferent_access

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 54


def nested_under_indifferent_access
  self
end

#regular_update

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 88


alias_method :regular_update, :update unless method_defined?(:regular_update)

#regular_writer

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 87


alias_method :regular_writer, :[]= unless method_defined?(:regular_writer)

#reject(*args, &block)

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 244


def reject(*args, &block)
  dup.tap { |hash| hash.reject!(*args, &block) }
end

#replace(other_hash)

Replaces the contents of this hash with other_hash.

h = { "a" => 100, "b" => 200 }
h.replace({ "c" => 300, "d" => 400 }) # => {"c"=>300, "d"=>400}

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 221


def replace(other_hash)
  super(self.class.new_from_hash_copying_default(other_hash))
end

#reverse_merge(other_hash)

Like #merge but the other way around: Merges the receiver into the argument and returns a new hash with indifferent access as result:

hash = ActiveSupport::HashWithIndifferentAccess.new
hash['a'] = nil
hash.reverse_merge(a: 0, b: 1) # => {"a"=>nil, "b"=>1}

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 208


def reverse_merge(other_hash)
  super(self.class.new_from_hash_copying_default(other_hash))
end

#reverse_merge!(other_hash)

Same semantics as #reverse_merge but modifies the receiver in-place.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 213


def reverse_merge!(other_hash)
  replace(reverse_merge( other_hash ))
end

#select(*args, &block)

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 240


def select(*args, &block)
  dup.tap { |hash| hash.select!(*args, &block) }
end

#store(key, value)

Alias for #[]=.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 100


alias_method :store, :[]=

#stringify_keys

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 232


def stringify_keys; dup end

#stringify_keys!

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 230


def stringify_keys!; self end

#symbolize_keys

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 236


def symbolize_keys; to_hash.symbolize_keys! end

#to_hash

Convert to a regular hash with string keys.

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 258


def to_hash
  _new_hash = Hash.new
  set_defaults(_new_hash)

  each do |key, value|
    _new_hash[key] = convert_value(value, for: :to_hash)
  end
  _new_hash
end

#to_options!

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 238


def to_options!; self end

#transform_values(*args, &block)

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 248


def transform_values(*args, &block)
  return to_enum(:transform_values) unless block_given?
  dup.tap { |hash| hash.transform_values!(*args, &block) }
end

#update(other_hash) Also known as: #merge!

Updates the receiver in-place, merging in the hash passed as argument:

hash_1 = ActiveSupport::HashWithIndifferentAccess.new
hash_1[:key] = 'value'

hash_2 = ActiveSupport::HashWithIndifferentAccess.new
hash_2[:key] = 'New Value!'

hash_1.update(hash_2) # => {"key"=>"New Value!"}

The argument can be either an HashWithIndifferentAccess or a regular ::Hash. In either case the merge respects the semantics of indifferent access.

If the argument is a regular hash with keys :key and “key” only one of the values end up in the receiver, but which one is unspecified.

When given a block, the value for duplicated keys will be determined by the result of invoking the block with the duplicated key, the value in the receiver, and the value in other_hash. The rules for duplicated keys follow the semantics of indifferent access:

hash_1[:key] = 10
hash_2['key'] = 12
hash_1.update(hash_2) { |key, old, new| old + new } # => {"key"=>22}

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 127


def update(other_hash)
  if other_hash.is_a? HashWithIndifferentAccess
    super(other_hash)
  else
    other_hash.to_hash.each_pair do |key, value|
      if block_given? && key?(key)
        value = yield(convert_key(key), self[key], value)
      end
      regular_writer(convert_key(key), convert_value(value))
    end
    self
  end
end

#values_at(*indices)

Returns an array of the values at the specified indices:

hash = ActiveSupport::HashWithIndifferentAccess.new
hash[:a] = 'x'
hash[:b] = 'y'
hash.values_at('a', 'b') # => ["x", "y"]

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 177


def values_at(*indices)
  indices.collect { |key| self[convert_key(key)] }
end

#with_indifferent_access

[ GitHub ]

# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 50


def with_indifferent_access
  dup
end

Class: ActiveSupport::HashWithIndifferentAccess

Overview

Class Method Summary

::Hash - Inherited

Instance Attribute Summary

::Hash - Inherited

Instance Method Summary

::Hash - Inherited

Constructor Details

.new(constructor = {}) ⇒ HashWithIndifferentAccess

Class Method Details

.[](*args)

.new_from_hash_copying_default(hash)

Instance Attribute Details

#extractable_options? ⇒ Boolean (readonly)

Instance Method Details

#[]=(key, value) Also known as: #store

#compact

#deep_stringify_keys

#deep_stringify_keys!

#deep_symbolize_keys

#default(key = nil)

#delete(key)

#dup

#fetch(key, *extras)

#has_key?(key)

#include?(key)

#key?(key) ⇒ Boolean Also known as: #include?, #has_key?, #member?

#member?(key)

#merge(hash, &block)

#merge!(other_hash)

#nested_under_indifferent_access

#regular_update

#regular_writer

#reject(*args, &block)

#replace(other_hash)

#reverse_merge(other_hash)

#reverse_merge!(other_hash)

#select(*args, &block)

#store(key, value)

#stringify_keys

#stringify_keys!

#symbolize_keys

#to_hash

#to_options!

#transform_values(*args, &block)

#update(other_hash) Also known as: #merge!

#values_at(*indices)

#with_indifferent_access

.new(constructor = {}) ⇒ `HashWithIndifferentAccess`

#extractable_options? ⇒ `Boolean` (readonly)

#key?(key) ⇒ `Boolean` Also known as: #include?, #has_key?, #member?