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_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
- 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.nil?
super()
elsif 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
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 184
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'
.
If the value is a Hash
or contains one or multiple Hashes, they will be converted to HashWithIndifferentAccess
.
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 101
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 197
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 390
def compact
dup.tap(&:compact!)
end
π See on GitHub
deep_symbolize_keys()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 334
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 239
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 317
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 224
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 280
def dup
copy_defaults(self.class.new(self))
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 325
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 211
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 267
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 167
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 287
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 342
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 312
def replace(other_hash)
super(cast(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 297
def reverse_merge(other_hash)
super(cast(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 303
def reverse_merge!(other_hash)
super(cast(other_hash))
end
π See on GitHub
select(*args, &block)
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 337
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 380
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 385
def slice!(*keys)
keys.map! { |key| convert_key(key) }
super
end
π See on GitHub
store(key, value, convert_value: true)
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'
.
If the value is a Hash
or contains one or multiple Hashes, they will be converted to HashWithIndifferentAccess
. unless βconvert_value: false` is set.
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 115
def store(key, value, convert_value: true)
value = convert_value(value, conversion: :assignment) if convert_value
regular_writer(convert_key(key), value)
end
π See on GitHub
symbolize_keys()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 332
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 395
def to_hash
copy = Hash[self]
copy.transform_values! { |v| convert_value_to_hash(v) }
copy_defaults(copy)
end
π See on GitHub
to_options!()
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 335
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 401
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 354
def transform_keys(hash = NOT_GIVEN, &block)
if NOT_GIVEN.equal?(hash)
if block_given?
self.class.new(super(&block))
else
to_enum(:transform_keys)
end
else
self.class.new(super)
end
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 366
def transform_keys!(hash = NOT_GIVEN, &block)
if NOT_GIVEN.equal?(hash)
if block_given?
replace(copy_defaults(transform_keys(&block)))
else
return to_enum(:transform_keys!)
end
else
replace(copy_defaults(transform_keys(hash, &block)))
end
self
end
π See on GitHub
transform_values(&block)
π Source code
# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 347
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 148
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 253
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