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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