Class: ActiveSupport::HashWithIndifferentAccess

Inherits:
Hash
  • Object
show all
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.

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.

Direct Known Subclasses

ActionCable::Connection::TestCookieJar

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Hash

#as_json, #assert_valid_keys, #compact_blank, #compact_blank!, #deep_dup, #deep_merge, #deep_merge!, #deep_symbolize_keys!, #deep_transform_keys, #deep_transform_keys!, #deep_transform_values, #deep_transform_values!, #except!, #extract!, from_trusted_xml, from_xml, #symbolize_keys!, #to_query, #to_xml

Constructor Details

#initialize(constructor = {}) ⇒ HashWithIndifferentAccess

Returns a new instance of HashWithIndifferentAccess.



67
68
69
70
71
72
73
74
75
76
77
78
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 67

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

Class Method Details

.[](*args) ⇒ Object 



80
81
82
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 80

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

Instance Method Details

#[](key) ⇒ Object

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



163
164
165
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 163

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

#[]=(key, value) ⇒ Object 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'.



93
94
95
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 93

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

#assoc(key) ⇒ Object

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



176
177
178
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 176

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

#compact ⇒ Object 



350
351
352
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 350

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

#deep_stringify_keys ⇒ Object 



304
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 304

def deep_stringify_keys; dup end

#deep_stringify_keys! ⇒ Object 



302
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 302

def deep_stringify_keys!; self end

#deep_symbolize_keys ⇒ Object 



309
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 309

def deep_symbolize_keys; to_hash.deep_symbolize_keys! end

#default(*args) ⇒ Object

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'



218
219
220
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 218

def default(*args)
  super(*args.map { |arg| convert_key(arg) })
end

#delete(key) ⇒ Object

Removes the specified key from the hash.



292
293
294
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 292

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

#dig(*args) ⇒ Object

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



203
204
205
206
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 203

def dig(*args)
  args[0] = convert_key(args[0]) if args.size > 0
  super(*args)
end

#dup ⇒ Object

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"



253
254
255
256
257
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 253

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

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



296
297
298
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 296

def except(*keys)
  slice(*self.keys - keys.map { |key| convert_key(key) })
end

#extractable_options? ⇒ Boolean

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

Returns:

  • (Boolean) 


55
56
57
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 55

def extractable_options?
  true
end

#fetch(key, *extras) ⇒ Object

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"



190
191
192
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 190

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

#fetch_values(*indices, &block) ⇒ Object

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"



241
242
243
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 241

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

#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

Returns:

  • (Boolean) 


146
147
148
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 146

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

#merge(*hashes, &block) ⇒ Object

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.



262
263
264
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 262

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

#nested_under_indifferent_access ⇒ Object 



63
64
65
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 63

def nested_under_indifferent_access
  self
end

#regular_update ⇒ Object 



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

alias_method :regular_update, :update

#regular_writer ⇒ Object 



84
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 84

alias_method :regular_writer, :[]=

#reject(*args, &block) ⇒ Object 



317
318
319
320
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 317

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

#replace(other_hash) ⇒ Object

Replaces the contents of this hash with other_hash.

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



287
288
289
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 287

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

#reverse_merge(other_hash) ⇒ Object 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}



272
273
274
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 272

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

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

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



278
279
280
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 278

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

#select(*args, &block) ⇒ Object 



312
313
314
315
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 312

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

#slice(*keys) ⇒ Object 



340
341
342
343
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 340

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

#slice!(*keys) ⇒ Object 



345
346
347
348
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 345

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

#stringify_keys ⇒ Object 



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

def stringify_keys; dup end

#stringify_keys! ⇒ Object 



301
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 301

def stringify_keys!; self end

#symbolize_keys ⇒ Object Also known as: to_options 



307
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 307

def symbolize_keys; to_hash.symbolize_keys! end

#to_hash ⇒ Object

Convert to a regular hash with string keys.



355
356
357
358
359
360
361
362
363
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 355

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! ⇒ Object 



310
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 310

def to_options!; self end

#transform_keys(*args, &block) ⇒ Object 



327
328
329
330
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 327

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

#transform_keys! ⇒ Object 



332
333
334
335
336
337
338
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 332

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) ⇒ Object 



322
323
324
325
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 322

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) ⇒ Object 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 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}



127
128
129
130
131
132
133
134
135
136
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 127

def update(*other_hashes, &block)
  if other_hashes.one?
    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) ⇒ Object

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"]



228
229
230
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 228

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

#with_indifferent_access ⇒ Object 



59
60
61
 
# File 'activesupport/lib/active_support/hash_with_indifferent_access.rb', line 59

def with_indifferent_access
  dup
end