Class: ActiveSupport::HashWithIndifferentAccess
- Defined in:
- 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.
Class Method Summary collapse
Instance Method Summary collapse
-
#[](key) ⇒ Object
Same as
Hash#[]
where the key passed as argument can be either a string or a symbol:. -
#[]=(key, value) ⇒ Object
(also: #store)
Assigns a new value to the hash:.
-
#assoc(key) ⇒ Object
Same as
Hash#assoc
where the key passed as argument can be either a string or a symbol:. - #compact ⇒ Object
- #deep_stringify_keys ⇒ Object
- #deep_stringify_keys! ⇒ Object
- #deep_symbolize_keys ⇒ Object
-
#default(*args) ⇒ Object
Same as
Hash#default
where the key passed as argument can be either a string or a symbol:. -
#delete(key) ⇒ Object
Removes the specified key from the hash.
-
#dig(*args) ⇒ Object
Same as
Hash#dig
where the key passed as argument can be either a string or a symbol:. -
#dup ⇒ Object
Returns a shallow copy of the hash.
- #except(*keys) ⇒ Object (also: #without)
-
#extractable_options? ⇒ Boolean
Returns
true
so thatArray#extract_options!
finds members of this class. -
#fetch(key, *extras) ⇒ Object
Same as
Hash#fetch
where the key passed as argument can be either a string or a symbol:. -
#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.
-
#initialize(constructor = {}) ⇒ HashWithIndifferentAccess
constructor
A new instance of HashWithIndifferentAccess.
-
#key?(key) ⇒ Boolean
(also: #include?, #has_key?, #member?)
Checks the hash for a key matching the argument passed in:.
-
#merge(hash, &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. - #nested_under_indifferent_access ⇒ Object
- #regular_update ⇒ Object
- #regular_writer ⇒ Object
- #reject(*args, &block) ⇒ Object
-
#replace(other_hash) ⇒ Object
Replaces the contents of this hash with other_hash.
-
#reverse_merge(other_hash) ⇒ Object
(also: #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:. -
#reverse_merge!(other_hash) ⇒ Object
(also: #with_defaults!)
Same semantics as
reverse_merge
but modifies the receiver in-place. - #select(*args, &block) ⇒ Object
- #slice(*keys) ⇒ Object
- #slice!(*keys) ⇒ Object
- #stringify_keys ⇒ Object
- #stringify_keys! ⇒ Object
- #symbolize_keys ⇒ Object (also: #to_options)
-
#to_hash ⇒ Object
Convert to a regular hash with string keys.
- #to_options! ⇒ Object
- #transform_keys(*args, &block) ⇒ Object
- #transform_keys! ⇒ Object
- #transform_values(*args, &block) ⇒ Object
-
#update(other_hash) ⇒ Object
(also: #merge!)
Updates the receiver in-place, merging in the hash passed as argument:.
-
#values_at(*keys) ⇒ Object
Returns an array of the values at the specified indices:.
- #with_indifferent_access ⇒ Object
Methods inherited from Hash
#as_json, #assert_valid_keys, #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.
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 67 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 |
Class Method Details
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
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# File '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'
.
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 93 def []=(key, value) regular_writer(convert_key(key), convert_value(value, for: :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
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 176 def assoc(key) super(convert_key(key)) end |
#compact ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 350 def compact dup.tap(&:compact!) end |
#deep_stringify_keys ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 304 def deep_stringify_keys; dup end |
#deep_stringify_keys! ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 302 def deep_stringify_keys!; self end |
#deep_symbolize_keys ⇒ Object
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# File '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'
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# File '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.
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# File '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
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# File '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"
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# File '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
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# File '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.
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 55 def 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"
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# File '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"
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# File '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
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 146 def key?(key) super(convert_key(key)) end |
#merge(hash, &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.
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 262 def merge(hash, &block) dup.update(hash, &block) end |
#nested_under_indifferent_access ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 63 def nested_under_indifferent_access self end |
#regular_update ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 85 alias_method :regular_update, :update |
#regular_writer ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 84 alias_method :regular_writer, :[]= |
#reject(*args, &block) ⇒ Object
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# File '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}
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# File '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}
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# File '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.
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# File '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
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# File '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
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# File '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
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 345 def slice!(*keys) keys.map! { |key| convert_key(key) } super end |
#stringify_keys ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 303 def stringify_keys; dup end |
#stringify_keys! ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 301 def stringify_keys!; self end |
#symbolize_keys ⇒ Object Also known as: to_options
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# File '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.
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# File '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, for: :to_hash) end _new_hash end |
#to_options! ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 310 def ; self end |
#transform_keys(*args, &block) ⇒ Object
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# File '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
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# File '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
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# File '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_hash) ⇒ Object Also known as: merge!
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}
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 124 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 |
#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"]
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# File '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
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 59 def with_indifferent_access dup end |