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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.

Methods
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Class Public methods

[](*args)

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 81
def self.[](*args)
  new.merge!(Hash[*args])
end

new(constructor = {})

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 68
def initialize(constructor = {})
  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
  else
    super(constructor)
  end
end

Instance Public methods

[](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

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 164
def [](key)
  super(convert_key(key))
end

[]=(key, value)

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'.

Also aliased as: regular_writer, store

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 94
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

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 177
def assoc(key)
  super(convert_key(key))
end

compact()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 355
def compact
  dup.tap(&:compact!)
end

deep_stringify_keys()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 309
def deep_stringify_keys; dup end

deep_stringify_keys!()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 307
def deep_stringify_keys!; self end

deep_symbolize_keys()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 314
def deep_symbolize_keys; to_hash.deep_symbolize_keys! end

default(*args)

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'

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 219
def default(*args)
  super(*args.map { |arg| convert_key(arg) })
end

delete(key)

Removes the specified key from the hash.

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 293
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

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 204
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"

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 254
def dup
  self.class.new(self).tap do |new_hash|
    set_defaults(new_hash)
  end
end

except(*keys)

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
Also aliased as: without

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 301
def except(*keys)
  slice(*self.keys - keys.map { |key| convert_key(key) })
end

extractable_options?()

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

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 56
def extractable_options?
  true
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"

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 191
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"

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 242
def fetch_values(*indices, &block)
  super(*indices.map { |key| convert_key(key) }, &block)
end

has_key?(key)

Alias for: key?

include?(key)

Alias for: key?

key?(key)

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
Also aliased as: include?, has_key?, member?

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 147
def key?(key)
  super(convert_key(key))
end

member?(key)

Alias for: 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.

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 263
def merge(*hashes, &block)
  dup.update(*hashes, &block)
end

merge!(*other_hashes, &block)

Alias for: update

nested_under_indifferent_access()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 64
def nested_under_indifferent_access
  self
end

regular_update(*other_hashes, &block)

Alias for: update

regular_writer(key, value)

Alias for: []=

reject(*args, &block)

Source: show | on GitHub 

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

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 288
def replace(other_hash)
  super(self.class.new(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}
Also aliased as: with_defaults

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 273
def reverse_merge(other_hash)
  super(self.class.new(other_hash))
end

reverse_merge!(other_hash)

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

Also aliased as: with_defaults!

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 279
def reverse_merge!(other_hash)
  super(self.class.new(other_hash))
end

select(*args, &block)

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 317
def select(*args, &block)
  return to_enum(:select) unless block_given?
  dup.tap { |hash| hash.select!(*args, &block) }
end

slice(*keys)

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 345
def slice(*keys)
  keys.map! { |key| convert_key(key) }
  self.class.new(super)
end

slice!(*keys)

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 350
def slice!(*keys)
  keys.map! { |key| convert_key(key) }
  super
end

store(key, value)

Alias for: []=

stringify_keys()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 308
def stringify_keys; dup end

stringify_keys!()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 306
def stringify_keys!; self end

symbolize_keys()

Also aliased as: to_options

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 312
def symbolize_keys; to_hash.symbolize_keys! end

to_hash()

Convert to a regular hash with string keys.

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 360
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

to_options!()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 315
def to_options!; self end

transform_keys(*args, &block)

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 332
def transform_keys(*args, &block)
  return to_enum(:transform_keys) unless block_given?
  dup.tap { |hash| hash.transform_keys!(*args, &block) }
end

transform_keys!()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 337
def transform_keys!
  return enum_for(:transform_keys!) { size } unless block_given?
  keys.each do |key|
    self[yield(key)] = delete(key)
  end
  self
end

transform_values(*args, &block)

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 327
def transform_values(*args, &block)
  return to_enum(:transform_values) unless block_given?
  dup.tap { |hash| hash.transform_values!(*args, &block) }
end

update(*other_hashes, &block)

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 ActiveSupport::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}
Also aliased as: regular_update, merge!

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 128
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"]

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 229
def values_at(*keys)
  super(*keys.map { |key| convert_key(key) })
end

with_defaults(other_hash)

Alias for: reverse_merge

with_defaults!(other_hash)

Alias for: reverse_merge!

with_indifferent_access()

Source: show | on GitHub 

# File rails/activesupport/lib/active_support/hash_with_indifferent_access.rb, line 60
def with_indifferent_access
  dup
end

without(*keys)

Alias for: except