Module: Enumerable
- Defined in:
- lib/active_support/core_ext/enumerable.rb,
lib/active_support/core_ext/object/json.rb
Instance Method Summary collapse
-
#as_json(options = nil) ⇒ Object
:nodoc:.
-
#exclude?(object) ⇒ Boolean
The negative of the
Enumerable#include?
. -
#index_by ⇒ Object
Convert an enumerable to a hash.
-
#many? ⇒ Boolean
Returns
true
if the enumerable has more than 1 element. -
#pluck(*keys) ⇒ Object
Convert an enumerable to an array based on the given key.
-
#sum(identity = nil, &block) ⇒ Object
Calculates a sum from the elements.
-
#without(*elements) ⇒ Object
Returns a copy of the enumerable without the specified elements.
Instance Method Details
#as_json(options = nil) ⇒ Object
:nodoc:
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# File 'lib/active_support/core_ext/object/json.rb', line 129 def as_json( = nil) #:nodoc: to_a.as_json() end |
#exclude?(object) ⇒ Boolean
The negative of the Enumerable#include?
. Returns true
if the collection does not include the object.
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# File 'lib/active_support/core_ext/enumerable.rb', line 83 def exclude?(object) !include?(object) end |
#index_by ⇒ Object
Convert an enumerable to a hash.
people.index_by(&:login)
=> { "nextangle" => <Person ...>, "chade-" => <Person ...>, ...}
people.index_by { |person| "#{person.first_name} #{person.last_name}" }
=> { "Chade- Fowlersburg-e" => <Person ...>, "David Heinemeier Hansson" => <Person ...>, ...}
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# File 'lib/active_support/core_ext/enumerable.rb', line 57 def index_by if block_given? Hash[map { |elem| [yield(elem), elem] }] else to_enum(:index_by) { size if respond_to?(:size) } end end |
#many? ⇒ Boolean
Returns true
if the enumerable has more than 1 element. Functionally equivalent to enum.to_a.size > 1
. Can be called with a block too, much like any?, so people.many? { |p| p.age > 26 }
returns true
if more than one person is over 26.
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# File 'lib/active_support/core_ext/enumerable.rb', line 69 def many? cnt = 0 if block_given? any? do |element| cnt += 1 if yield element cnt > 1 end else any? { (cnt += 1) > 1 } end end |
#pluck(*keys) ⇒ Object
Convert an enumerable to an array based on the given key.
[{ name: "David" }, { name: "Rafael" }, { name: "Aaron" }].pluck(:name)
=> ["David", "Rafael", "Aaron"]
[{ id: 1, name: "David" }, { id: 2, name: "Rafael" }].pluck(:id, :name)
=> [[1, "David"], [2, "Rafael"]]
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# File 'lib/active_support/core_ext/enumerable.rb', line 105 def pluck(*keys) if keys.many? map { |element| keys.map { |key| element[key] } } else map { |element| element[keys.first] } end end |
#sum(identity = nil, &block) ⇒ Object
Calculates a sum from the elements.
payments.sum { |p| p.price * p.tax_rate }
payments.sum(&:price)
The latter is a shortcut for:
payments.inject(0) { |sum, p| sum + p.price }
It can also calculate the sum without the use of a block.
[5, 15, 10].sum # => 30
['foo', 'bar'].sum # => "foobar"
[[1, 2], [3, 1, 5]].sum # => [1, 2, 3, 1, 5]
The default sum of an empty list is zero. You can override this default:
[].sum(Payment.new(0)) { |i| i.amount } # => Payment.new(0)
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# File 'lib/active_support/core_ext/enumerable.rb', line 31 def sum(identity = nil, &block) if identity _original_sum_with_required_identity(identity, &block) elsif block_given? map(&block).sum(identity) else inject(:+) || 0 end end |
#without(*elements) ⇒ Object
Returns a copy of the enumerable without the specified elements.
["David", "Rafael", "Aaron", "Todd"].without "Aaron", "Todd"
=> ["David", "Rafael"]
{foo: 1, bar: 2, baz: 3}.without :bar
=> {foo: 1, baz: 3}
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# File 'lib/active_support/core_ext/enumerable.rb', line 94 def without(*elements) reject { |element| elements.include?(element) } end |