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Module: Enumerable

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Extended In:
Rails::Autoloaders
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::Dot, ActionDispatch::Journey::Nodes::Dummy, ActionDispatch::Journey::Nodes::Group, ActionDispatch::Journey::Nodes::Literal, ActionDispatch::Journey::Nodes::Node, ActionDispatch::Journey::Nodes::Or, ActionDispatch::Journey::Nodes::Slash, 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::CollectionRenderer::CollectionIterator, ActionView::CollectionRenderer::MixedCollectionIterator, ActionView::CollectionRenderer::PreloadCollectionIterator, ActionView::CollectionRenderer::SameCollectionIterator, 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, ActiveSupport::DescendantsTracker::DescendantsArray, ::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

Constant Summary

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 96



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



  

    #compact_blank  
  



  

    

Returns a new ::Array without the blank items. Uses Object#blank? for determining if an item is blank.



[1, "", nil, 2, " ", [], {}, false, true].compact_blank
# =>  [1, 2, true]

Set.new([nil, "", 1, 2])
# => [2, 1] (or [1, 2])



When called on a ::Hash, returns a new ::Hash without the blank values.



{ a: "", b: 1, c: nil, d: [], e: false, f: true }.compact_blank
#=> { b: 1, f: true }


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 191



def compact_blank
  reject(&:blank?)
end


  








  

    #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 121



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


  








  

    #excluding(*elements)  
  



  

    

Returns a copy of the enumerable excluding the specified elements.



["David", "Rafael", "Aaron", "Todd"].excluding "Aaron", "Todd"
# => ["David", "Rafael"]

["David", "Rafael", "Aaron", "Todd"].excluding %w[ Aaron Todd ]
# => ["David", "Rafael"]

{foo: 1, bar: 2, baz: 3}.excluding :bar
# => {foo: 1, baz: 3}


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 135



def excluding(*elements)
  elements.flatten!(1)
  reject { |element| elements.include?(element) }
end


  








  

    #including(*elements)  
  



  

    

Returns a new array that includes the passed elements.



[ 1, 2, 3 ].including(4, 5)
# => [ 1, 2, 3, 4, 5 ]

["David", "Rafael"].including %w[ Aaron Todd ]
# => ["David", "Rafael", "Aaron", "Todd"]


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 115



def including(*elements)
  to_a.including(*elements)
end


  








  

    #index_by  
  



  

    

Convert an enumerable to a hash, using the block result as the key and the element as the value.



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 55



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


  








  

    #index_with(default = INDEX_WITH_DEFAULT)  
  



  

    

Convert an enumerable to a hash, using the element as the key and the block result as the value.



post = Post.new(title: "hey there", body: "what's up?")

%i( title body ).index_with { |attr_name| post.public_send(attr_name) }
# => { title: "hey there", body: "what's up?" }



If an argument is passed instead of a block, it will be used as the value for all elements:



%i( created_at updated_at ).index_with(Time.now)
# => { created_at: 2020-03-09 22:31:47, updated_at: 2020-03-09 22:31:47 }


  



  [ GitHub ]


  

  


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



def index_with(default = INDEX_WITH_DEFAULT)
  if block_given?
    result = {}
    each { |elem| result[elem] = yield(elem) }
    result
  elsif default != INDEX_WITH_DEFAULT
    result = {}
    each { |elem| result[elem] = default }
    result
  else
    to_enum(:index_with) { size if respond_to?(:size) }
  end
end


  








  

    #pick(*keys)  
  



  

    

Extract the given key from the first element in the enumerable.



[{ name: "David" }, { name: "Rafael" }, { name: "Aaron" }].pick(:name)
# => "David"

[{ id: 1, name: "David" }, { id: 2, name: "Rafael" }].pick(:id, :name)
# => [1, "David"]


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 168



def pick(*keys)
  return if none?

  if keys.many?
    keys.map { |key| first[key] }
  else
    first[keys.first]
  end
end


  








  

    #pluck(*keys)  
  



  

    

Extract the given key from each element in the enumerable.



[{ 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 152



def pluck(*keys)
  if keys.many?
    map { |element| keys.map { |key| element[key] } }
  else
    key = keys.first
    map { |element| element[key] }
  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)


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 37



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)  
  



  

    

Alias for #excluding.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/core_ext/enumerable.rb', line 141



def without(*elements)
  excluding(*elements)
end