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.
Methods
- []
- []
- []=
- assoc
- compact
- deep_stringify_keys
- deep_stringify_keys!
- deep_symbolize_keys
- default
- delete
- dig
- dup
- except
- extractable_options?
- fetch
- fetch_values
- has_key?
- include?
- key?
- member?
- merge
- merge!
- nested_under_indifferent_access
- new
- regular_update
- regular_writer
- reject
- replace
- reverse_merge
- reverse_merge!
- select
- slice
- slice!
- store
- stringify_keys
- stringify_keys!
- symbolize_keys
- to_hash
- to_options
- to_options!
- to_proc
- transform_keys
- transform_keys!
- transform_values
- update
- values_at
- with_defaults
- with_defaults!
- with_indifferent_access
- without
Class Public methods
[](*args)
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 85
def self.[](*args)
new.merge!(Hash[*args])
end
π See on GitHub
new(constructor = nil)
π Source code
# 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
π See on GitHub
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
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 168
def [](key)
super(convert_key(key))
end
π See on GitHub
[]=(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'
.
π Source code
# 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
π See on GitHub
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
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 181
def assoc(key)
super(convert_key(key))
end
π See on GitHub
compact()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 375
def compact
dup.tap(&:compact!)
end
π See on GitHub
deep_stringify_keys()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 319
def deep_stringify_keys; dup end
π See on GitHub
deep_stringify_keys!()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 317
def deep_stringify_keys!; self end
π See on GitHub
deep_symbolize_keys()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 324
def deep_symbolize_keys; to_hash.deep_symbolize_keys! end
π See on GitHub
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'
π Source code
# 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
π See on GitHub
delete(key)
Removes the specified key from the hash.
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 303
def delete(key)
super(convert_key(key))
end
π See on GitHub
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
π Source code
# 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
π See on GitHub
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"
π Source code
# 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
π See on GitHub
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
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 311
def except(*keys)
dup.except!(*keys)
end
π See on GitHub
extractable_options?()
Returns true
so that Array#extract_options!
finds members of this class.
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 58
def extractable_options?
true
end
π See on GitHub
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"
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 195
def fetch(key, *extras)
super(convert_key(key), *extras)
end
π See on GitHub
fetch_values(*indices, &block)
Returns an array of the values at the specified indices, but also raises an exception when one of the keys canβt 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"
π Source code
# 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
π See on GitHub
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
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 151
def key?(key)
super(convert_key(key))
end
π See on GitHub
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.
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 273
def merge(*hashes, &block)
dup.update(*hashes, &block)
end
π See on GitHub
nested_under_indifferent_access()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 66
def nested_under_indifferent_access
self
end
π See on GitHub
reject(*args, &block)
π Source code
# 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
π See on GitHub
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}
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 298
def replace(other_hash)
super(self.class.new(other_hash))
end
π See on GitHub
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}
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 283
def reverse_merge(other_hash)
super(self.class.new(other_hash))
end
π See on GitHub
reverse_merge!(other_hash)
Same semantics as reverse_merge
but modifies the receiver in-place.
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 289
def reverse_merge!(other_hash)
super(self.class.new(other_hash))
end
π See on GitHub
select(*args, &block)
π Source code
# 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
π See on GitHub
slice(*keys)
π Source code
# 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
π See on GitHub
slice!(*keys)
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 370
def slice!(*keys)
keys.map! { |key| convert_key(key) }
super
end
π See on GitHub
stringify_keys()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 318
def stringify_keys; dup end
π See on GitHub
stringify_keys!()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 316
def stringify_keys!; self end
π See on GitHub
symbolize_keys()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 322
def symbolize_keys; to_hash.symbolize_keys! end
π See on GitHub
to_hash()
Convert to a regular hash with string keys.
π Source code
# 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
π See on GitHub
to_options!()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 325
def to_options!; self end
π See on GitHub
to_proc()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 390
def to_proc
proc { |key| self[key] }
end
π See on GitHub
transform_keys(hash = NOT_GIVEN, &block)
π Source code
# 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
π See on GitHub
transform_keys!(hash = NOT_GIVEN, &block)
π Source code
# 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
π See on GitHub
transform_values(&block)
π Source code
# 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
π See on GitHub
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}
π Source code
# 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
π See on GitHub
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"]
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 237
def values_at(*keys)
keys.map! { |key| convert_key(key) }
super
end
π See on GitHub
with_indifferent_access()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 62
def with_indifferent_access
dup
end
π See on GitHub