ActiveSupport::HashWithIndifferentAccess (original) (raw)

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

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Class Public methods

Source: show | on GitHub

def self. new.merge!(Hash[*args]) end

new(constructor = nil)Link

Source: show | on GitHub

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

Instance Public methods

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'.

Source: show | on GitHub

def []=(key, value) regular_writer(convert_key(key), convert_value(value, conversion: :assignment)) end

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

Source: show | on GitHub

def assoc(key) super(convert_key(key)) end

Source: show | on GitHub

def deep_symbolize_keys; to_hash.deep_symbolize_keys! end

default(key = (no_key = true))Link

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'

Source: show | on GitHub

def default(key = (no_key = true)) if no_key super() else super(convert_key(key)) end end

Removes the specified key from the hash.

Source: show | on GitHub

def delete(key) super(convert_key(key)) end

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

Source: show | on GitHub

def dig(*args) args[0] = convert_key(args[0]) if args.size > 0 super(*args) end

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"

Source: show | on GitHub

def dup self.class.new(self).tap do |new_hash| set_defaults(new_hash) end end

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

Source: show | on GitHub

def except(*keys) dup.except!(*keys) end

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"

Source: show | on GitHub

def fetch(key, *extras) super(convert_key(key), *extras) end

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"

Source: show | on GitHub

def fetch_values(*indices, &block) indices.map! { |key| convert_key(key) } super end

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

Source: show | on GitHub

def key?(key) super(convert_key(key)) end

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.

Source: show | on GitHub

def merge(*hashes, &block) dup.update(*hashes, &block) end

Source: show | on GitHub

def nested_under_indifferent_access self end

Alias for: []=

Source: show | on GitHub

def reject(*args, &block) return to_enum(:reject) unless block_given? dup.tap { |hash| hash.reject!(*args, &block) } end

Replaces the contents of this hash with other_hash.

h = { "a" => 100, "b" => 200 }
h.replace({ "c" => 300, "d" => 400 }) # => {"c"=>300, "d"=>400}

Source: show | on GitHub

def replace(other_hash) super(self.class.new(other_hash)) end

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}

Source: show | on GitHub

def reverse_merge(other_hash) super(self.class.new(other_hash)) end

Same semantics as reverse_merge but modifies the receiver in-place.

Source: show | on GitHub

def reverse_merge!(other_hash) super(self.class.new(other_hash)) end

Source: show | on GitHub

def select(*args, &block) return to_enum(:select) unless block_given? dup.tap { |hash| hash.select!(*args, &block) } end

Source: show | on GitHub

def slice(*keys) keys.map! { |key| convert_key(key) } self.class.new(super) end

Source: show | on GitHub

def slice!(*keys) keys.map! { |key| convert_key(key) } super end

Alias for: []=

Source: show | on GitHub

def symbolize_keys; to_hash.symbolize_keys! end

Convert to a regular hash with string keys.

Source: show | on GitHub

def to_hash copy = Hash[self] copy.transform_values! { |v| convert_value_to_hash(v) } set_defaults(copy) copy end

transform_keys(hash = NOT_GIVEN, &block)Link

Source: show | on GitHub

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

transform_keys!(hash = NOT_GIVEN, &block)Link

Source: show | on GitHub

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

Source: show | on GitHub

def transform_values(&block) return to_enum(:transform_values) unless block_given? dup.tap { |hash| hash.transform_values!(&block) } end

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}

Source: show | on GitHub

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

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"]

Source: show | on GitHub

def values_at(*keys) keys.map! { |key| convert_key(key) } super end