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.
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 83 def self.[](*args) new.merge!(Hash[*args]) end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 68
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 # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 166 def [](key) super(convert_key(key)) end
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
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 96 def []=(key, value) regular_writer(convert_key(key), convert_value(value, conversion: :assignment)) end
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'.
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 179 def assoc(key) super(convert_key(key)) end
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
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 357 def compact dup.tap(&:compact!) end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 311 def deep_stringify_keys; dup end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 309 def deep_stringify_keys!; self end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 316 def deep_symbolize_keys; to_hash.deep_symbolize_keys! end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 221
def default(*args)
super(*args.map { |arg| convert_key(arg) })
end 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'
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 295 def delete(key) super(convert_key(key)) end
Removes the specified key from the hash.
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 206 def dig(*args) args[0] = convert_key(args[0]) if args.size > 0 super(*args) end
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
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 256
def dup
self.class.new(self).tap do |new_hash|
set_defaults(new_hash)
end
end 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"
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 303
def except(*keys)
slice(*self.keys - keys.map { |key| convert_key(key) })
end 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
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 56 def extractable_options? true end
Returns true so that Array#extract_options! finds members of this class.
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 193 def fetch(key, *extras) super(convert_key(key), *extras) end
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"
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 244
def fetch_values(*indices, &block)
super(*indices.map { |key| convert_key(key) }, &block)
end 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"
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 149 def key?(key) super(convert_key(key)) end
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
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 265 def merge(*hashes, &block) dup.update(*hashes, &block) end
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.
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 64 def nested_under_indifferent_access self end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 324
def reject(*args, &block)
return to_enum(:reject) unless block_given?
dup.tap { |hash| hash.reject!(*args, &block) }
end # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 290 def replace(other_hash) super(self.class.new(other_hash)) end
Replaces the contents of this hash with other_hash.
h = { "a" => 100, "b" => 200 }
h.replace({ "c" => 300, "d" => 400 }) # => {"c"=>300, "d"=>400}
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 275 def reverse_merge(other_hash) super(self.class.new(other_hash)) end
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}
Hash#reverse_merge # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 281 def reverse_merge!(other_hash) super(self.class.new(other_hash)) end
Same semantics as reverse_merge but modifies the receiver in-place.
Hash#reverse_merge! # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 319
def select(*args, &block)
return to_enum(:select) unless block_given?
dup.tap { |hash| hash.select!(*args, &block) }
end # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 347
def slice(*keys)
keys.map! { |key| convert_key(key) }
self.class.new(super)
end # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 352
def slice!(*keys)
keys.map! { |key| convert_key(key) }
super
end Hash#slice! # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 310 def stringify_keys; dup end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 308 def stringify_keys!; self end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 314 def symbolize_keys; to_hash.symbolize_keys! end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 362
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 Convert to a regular hash with string keys.
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 317 def to_options!; self end
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 334
def transform_keys(*args, &block)
return to_enum(:transform_keys) unless block_given?
dup.tap { |hash| hash.transform_keys!(*args, &block) }
end # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 339
def transform_keys!
return enum_for(:transform_keys!) { size } unless block_given?
keys.each do |key|
self[yield(key)] = delete(key)
end
self
end # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 329
def transform_values(*args, &block)
return to_enum(:transform_values) unless block_given?
dup.tap { |hash| hash.transform_values!(*args, &block) }
end # File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 130
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 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}
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 231
def values_at(*keys)
super(*keys.map { |key| convert_key(key) })
end 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"]
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 60 def with_indifferent_access dup end
© 2004–2021 David Heinemeier Hansson
Licensed under the MIT License.