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Module: Enumerable

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Included In:
ActionController::MiddlewareStack, ActionController::RequestForgeryProtection::ProtectionMethods::NullSession::NullCookieJar, ActionDispatch::Cookies::CookieJar, ::ActionDispatch::Flash::FlashHash, ::ActionDispatch::Http::Headers, ActionDispatch::Journey::Nodes::Binary, ActionDispatch::Journey::Nodes::Cat, ActionDispatch::Journey::Nodes::Dummy, ActionDispatch::Journey::Nodes::Group, ActionDispatch::Journey::Nodes::Literal, ActionDispatch::Journey::Nodes::Node, ActionDispatch::Journey::Nodes::Or, ActionDispatch::Journey::Nodes::Star, ActionDispatch::Journey::Nodes::Symbol, ActionDispatch::Journey::Nodes::Terminal, ActionDispatch::Journey::Nodes::Unary, ActionDispatch::Journey::Routes, ::ActionDispatch::MiddlewareStack, ActionDispatch::Routing::Mapper::Scope, ActionDispatch::Routing::RouteSet::NamedRouteCollection, ActionView::PathSet, ::ActiveModel::Errors, ::ActiveRecord::AssociationRelation, ::ActiveRecord::Associations::CollectionProxy, ActiveRecord::Associations::JoinDependency::JoinAssociation, ActiveRecord::Associations::JoinDependency::JoinBase, ActiveRecord::Associations::JoinDependency::JoinPart, ::ActiveRecord::Batches::BatchEnumerator, ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter::StatementPool, ActiveRecord::ConnectionAdapters::PostgreSQLAdapter::StatementPool, ActiveRecord::ConnectionAdapters::SQLite3Adapter::StatementPool, ActiveRecord::ConnectionAdapters::StatementPool, ActiveRecord::Fixture, ActiveRecord::FixtureSet::File, ::ActiveRecord::Relation, ::ActiveRecord::Result, ActiveSupport::Callbacks::CallbackChain, ::ActiveSupport::Dependencies::WatchStack, ::Mime::Mimes, ::Rails::Engine::Railties, ::Rails::Paths::Path
Defined in: activesupport/lib/active_support/core_ext/enumerable.rb,
activesupport/lib/active_support/core_ext/object/json.rb

Instance Attribute Summary

Instance Method Summary

Instance Attribute Details

#many?Boolean (readonly)

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.

[ GitHub ]

  
# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 78

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

Instance Method Details

#exclude?(object) ⇒ Boolean

The negative of the Enumerable#include?. Returns true if the collection does not include the object.

[ GitHub ]

  
# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 92

def exclude?(object)
  !include?(object)
end

#index_by

Convert an enumerable to a hash.

people.index_by(&:)
# => { "nextangle" => <Person ...>, "chade-" => <Person ...>, ...}
people.index_by { |person| "#{person.first_name} #{person.last_name}" }
# => { "Chade- Fowlersburg-e" => <Person ...>, "David Heinemeier Hansson" => <Person ...>, ...}
[ GitHub ]

  
# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 64

def index_by
  if block_given?
    result = {}
    each { |elem| result[yield(elem)] = elem }
    result
  else
    to_enum(:index_by) { size if respond_to?(:size) }
  end
end

#pluck(*keys)

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"]]
[ GitHub ]

  
# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 114

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)

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)

See additional method definition at line 38.

[ GitHub ]

  
# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 48

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)

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}
[ GitHub ]

  
# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 103

def without(*elements)
  reject { |element| elements.include?(element) }
end