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:.
- #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.
-
#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:. -
#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
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
Same semantics as
reverse_merge
but modifies the receiver in-place. - #select(*args, &block) ⇒ Object
- #stringify_keys ⇒ Object
- #stringify_keys! ⇒ Object
- #symbolize_keys ⇒ Object
-
#to_hash ⇒ Object
Convert to a regular hash with string keys.
- #to_options! ⇒ 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(*indices) ⇒ Object
Returns an array of the values at the specified indices:.
- #with_indifferent_access ⇒ Object
Methods inherited from Hash
#as_json, #assert_valid_keys, #compact!, #deep_dup, #deep_merge, #deep_merge!, #deep_symbolize_keys!, #deep_transform_keys, #deep_transform_keys!, #except, #except!, #extract!, from_trusted_xml, from_xml, #slice, #slice!, #symbolize_keys!, #to_query, #to_xml, #transform_keys, #transform_keys!, #transform_values!
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 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 |
Class Method Details
.[](*args) ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 77 def self.[](*args) new.merge!(Hash[*args]) end |
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 160 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 90 def []=(key, value) regular_writer(convert_key(key), convert_value(value, for: :assignment)) end |
#compact ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 292 def compact dup.tap(&:compact!) end |
#deep_stringify_keys ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 270 def deep_stringify_keys; dup end |
#deep_stringify_keys! ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 268 def deep_stringify_keys!; self end |
#deep_symbolize_keys ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 274 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 204 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 263 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 188 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 226 def dup self.class.new(self).tap do |new_hash| set_defaults(new_hash) end 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 52 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 174 def fetch(key, *extras) super(convert_key(key), *extras) 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 143 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 235 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 60 def nested_under_indifferent_access self end |
#regular_update ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 82 alias_method :regular_update, :update |
#regular_writer ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 81 alias_method :regular_writer, :[]= |
#reject(*args, &block) ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 282 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 258 def replace(other_hash) super(self.class.new(other_hash)) end |
#reverse_merge(other_hash) ⇒ Object
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 245 def reverse_merge(other_hash) super(self.class.new(other_hash)) end |
#reverse_merge!(other_hash) ⇒ Object
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 250 def reverse_merge!(other_hash) replace(reverse_merge(other_hash)) end |
#select(*args, &block) ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 277 def select(*args, &block) return to_enum(:select) unless block_given? dup.tap { |hash| hash.select!(*args, &block) } end |
#stringify_keys ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 269 def stringify_keys; dup end |
#stringify_keys! ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 267 def stringify_keys!; self end |
#symbolize_keys ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 273 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 297 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 275 def ; self end |
#transform_values(*args, &block) ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 287 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 121 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(*indices) ⇒ 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 214 def values_at(*indices) indices.collect { |key| self[convert_key(key)] } end |
#with_indifferent_access ⇒ Object
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# File 'lib/active_support/hash_with_indifferent_access.rb', line 56 def with_indifferent_access dup end |