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Class: ActiveSupport::HashWithIndifferentAccess

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
ActionCable::Connection::TestCookieJar
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::Hash
Instance Chain:
self, ::Hash
Inherits: Hash
Defined in: activesupport/lib/active_support/hash_with_indifferent_access.rb

Overview

Hash With Indifferent Access

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.

To access this class outside of Rails, require the core extension with:

require "active_support/core_ext/hash/indifferent_access"

which will, in turn, require this file.

Class Method Summary

::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

::Hash - Inherited

#extractable_options?

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

Instance Method Summary

::Hash - Inherited

#assert_valid_keys

Validates all keys in a hash match *valid_keys, raising ArgumentError on a mismatch.
#blank?

A hash is blank if it’s empty:
#compact_blank!

Removes all blank values from the ::Hash in place and returns self.
#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 converts 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 converts 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 converts all keys by using the block operation.
#deep_transform_values

Returns a new hash with all values converted by the block operation.
#deep_transform_values!

Destructively converts all values by using the block operation.
#except

Returns a hash that includes everything except given keys.
#except!

Removes the given keys from hash and returns it.
#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!

Replaces the hash with only the given keys.
#stringify_keys

Returns a new hash with all keys converted to strings.
#stringify_keys!

Destructively converts 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 converts 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:
#with_defaults

Alias for Hash#reverse_merge.
#with_defaults!

Alias for Hash#reverse_merge!.
#with_indifferent_access

Returns an HashWithIndifferentAccess out of its receiver:

Constructor Details

.new(constructor = nil) ⇒ HashWithIndifferentAccess

[ GitHub ] 

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 70



def initialize(constructor = nil)
  if constructor.respond_to?(:to_hash)
    super()
    update(constructor)

    hash = constructor.is_a?(Hash) ? constructor : constructor.to_hash
    self.default = hash.default if hash.default
    self.default_proc = hash.default_proc if hash.default_proc
  elsif constructor.nil?
    super()
  else
    super(constructor)
  end
end


  







Class Method Details



  

    .[](*args)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 85



def self.[](*args)
  new.merge!(Hash[*args])
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 58



def extractable_options?
  true
end


  







Instance Method Details



  

    #[](key)  
  



  

    

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



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

counters['foo'] # => 1
counters[:foo]  # => 1
counters[:zoo]  # => nil


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 168



def [](key)
  super(convert_key(key))
end


  








  

    #[]=(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 98



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


  








  

    #assoc(key)  
  



  

    

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



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

counters.assoc('foo') # => ["foo", 1]
counters.assoc(:foo)  # => ["foo", 1]
counters.assoc(:zoo)  # => nil


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 181



def assoc(key)
  super(convert_key(key))
end


  








  

    #compact  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 375



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


  








  

    #deep_stringify_keys  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 319



def deep_stringify_keys; dup end


  








  

    #deep_stringify_keys!  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 317



def deep_stringify_keys!; self end


  








  

    #deep_symbolize_keys  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 324



def deep_symbolize_keys; to_hash.deep_symbolize_keys! end


  








  

    #default(key = (no_key = true))  
  



  

    

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



hash = ActiveSupport::HashWithIndifferentAccess.new(1)
hash.default                   # => 1

hash = ActiveSupport::HashWithIndifferentAccess.new { |hash, key| key }
hash.default                   # => nil
hash.default('foo')            # => 'foo'
hash.default(:foo)             # => 'foo'


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 223



def default(key = (no_key = true))
  if no_key
    super()
  else
    super(convert_key(key))
  end
end


  








  

    #delete(key)  
  



  

    

Removes the specified key from the hash.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 303



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


  








  

    #dig(*args)  
  



  

    

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



counters = ActiveSupport::HashWithIndifferentAccess.new
counters[:foo] = { bar: 1 }

counters.dig('foo', 'bar')     # => 1
counters.dig(:foo, :bar)       # => 1
counters.dig(:zoo)             # => nil


  



  [ GitHub ]


  

  


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



def dig(*args)
  args[0] = convert_key(args[0]) if args.size > 0
  super(*args)
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] # => "c"
dup[:a][:c]  # => "c"


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 264



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


  








  

    #except(*keys)  
    Also known as: #without
  



  

    

Returns a hash with indifferent access that includes everything except given keys.



hash = { a: "x", b: "y", c: 10 }.with_indifferent_access
hash.except(:a, "b") # => {c: 10}.with_indifferent_access
hash                 # => { a: "x", b: "y", c: 10 }.with_indifferent_access


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 311



def except(*keys)
  dup.except!(*keys)
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 195



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


  








  

    #fetch_values(*indices, &block)  
  



  

    

Returns an array of the values at the specified indices, but also raises an exception when one of the keys can’t be found.



hash = ActiveSupport::HashWithIndifferentAccess.new
hash[:a] = 'x'
hash[:b] = 'y'
hash.fetch_values('a', 'b') # => ["x", "y"]
hash.fetch_values('a', 'c') { |key| 'z' } # => ["x", "z"]
hash.fetch_values('a', 'c') # => KeyError: key not found: "c"


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 251



def fetch_values(*indices, &block)
  indices.map! { |key| convert_key(key) }
  super
end


  








  

    #has_key?(key)  
  



  

    

Alias for #key?.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 156



alias_method :has_key?, :key?


  








  

    #include?(key)  
  



  

    

Alias for #key?.


  



  [ GitHub ]


  

  


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



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 151



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 157



alias_method :member?, :key?


  








  

    #merge(*hashes, &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 273



def merge(*hashes, &block)
  dup.update(*hashes, &block)
end


  








  

    #merge!(*other_hashes, &block)  
  



  

    

Alias for #update.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 143



alias_method :merge!, :update


  








  

    #nested_under_indifferent_access  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 66



def nested_under_indifferent_access
  self
end


  








  

    #regular_update  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 90



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


  








  

    #regular_writer  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 89



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


  








  

    #reject(*args, &block)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 332



def reject(*args, &block)
  return to_enum(:reject) unless block_given?
  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 298



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


  








  

    #reverse_merge(other_hash)  
    Also known as: #with_defaults
  



  

    

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 283



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


  








  

    #reverse_merge!(other_hash)  
    Also known as: #with_defaults!
  



  

    

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


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 289



def reverse_merge!(other_hash)
  super(self.class.new(other_hash))
end


  








  

    #select(*args, &block)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 327



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


  








  

    #slice(*keys)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 365



def slice(*keys)
  keys.map! { |key| convert_key(key) }
  self.class.new(super)
end


  








  

    #slice!(*keys)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 370



def slice!(*keys)
  keys.map! { |key| convert_key(key) }
  super
end


  








  

    #store(key, value)  
  



  

    

Alias for #[]=.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 102



alias_method :store, :[]=


  








  

    #stringify_keys  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 318



def stringify_keys; dup end


  








  

    #stringify_keys!  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 316



def stringify_keys!; self end


  








  

    #symbolize_keys  
    Also known as: #to_options
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 322



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 380



def to_hash
  _new_hash = Hash.new
  set_defaults(_new_hash)

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


  








  

    #to_options  
  



  

    

Alias for #symbolize_keys.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 323



alias_method :to_options, :symbolize_keys


  








  

    #to_options!  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 325



def to_options!; self end


  








  

    #transform_keys(hash = NOT_GIVEN, &block)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 344



def transform_keys(hash = NOT_GIVEN, &block)
  return to_enum(:transform_keys) if NOT_GIVEN.equal?(hash) && !block_given?
  dup.tap { |h| h.transform_keys!(hash, &block) }
end


  








  

    #transform_keys!(hash = NOT_GIVEN, &block)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 349



def transform_keys!(hash = NOT_GIVEN, &block)
  return to_enum(:transform_keys!) if NOT_GIVEN.equal?(hash) && !block_given?

  if hash.nil?
    super
  elsif NOT_GIVEN.equal?(hash)
    keys.each { |key| self[yield(key)] = delete(key) }
  elsif block_given?
    keys.each { |key| self[hash[key] || yield(key)] = delete(key) }
  else
    keys.each { |key| self[hash[key] || key] = delete(key) }
  end

  self
end


  








  

    #transform_values(&block)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 337



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


  








  

    #update(*other_hashes, &block)  
    Also known as: #merge!
  



  

    

Updates the receiver in-place, merging in the hashes passed as arguments:



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!"}

hash = ActiveSupport::HashWithIndifferentAccess.new
hash.update({ "a" => 1 }, { "b" => 2 }) # => { "a" => 1, "b" => 2 }



The arguments 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 132



def update(*other_hashes, &block)
  if other_hashes.size == 1
    update_with_single_argument(other_hashes.first, block)
  else
    other_hashes.each do |other_hash|
      update_with_single_argument(other_hash, block)
    end
  end
  self
end


  








  

    #values_at(*keys)  
  



  

    

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 237



def values_at(*keys)
  keys.map! { |key| convert_key(key) }
  super
end


  








  

    #with_defaults(other_hash)  
  



  

    

Alias for #reverse_merge.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 286



alias_method :with_defaults, :reverse_merge


  








  

    #with_defaults!(other_hash)  
  



  

    

Alias for #reverse_merge!.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 292



alias_method :with_defaults!, :reverse_merge!


  








  

    #with_indifferent_access  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 62



def with_indifferent_access
  dup
end


  








  

    #without(*keys)  
  



  

    

Alias for #except.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 314



alias_method :without, :except