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.
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# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 64 def initialize(constructor = {}) if constructor.respond_to?(:to_hash) super() update(constructor) hash = 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
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
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'.
Removes the specified key from the hash.
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"
Returns true so that Array#extract_options! finds
members of this class.
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"
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
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.
Replaces the contents of this hash with other_hash.
h = { "a" => 100, "b" => 200 }
h.replace({ "c" => 300, "d" => 400 }) # => {"c"=>300, "d"=>400}
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}
Same semantics as reverse_merge but modifies the receiver
in-place.
Convert to a regular hash with string keys.
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
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 131 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
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 292 def convert_value(value, options = {}) # :doc: if value.is_a? Hash if options[:for] == :to_hash value.to_hash else value.nested_under_indifferent_access end elsif value.is_a?(Array) if options[:for] != :assignment || value.frozen? value = value.dup end value.map! { |e| convert_value(e, options) } else value end end