Enumerable

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, false]).compact_blank
# => [1]

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 }

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 184
  def compact_blank
    reject(&:blank?)
  end

🔎 See on GitHub

exclude?(object)

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

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 118
  def exclude?(object)
    !include?(object)
  end

🔎 See on GitHub

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}

Also aliased as: without

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 132
  def excluding(*elements)
    elements.flatten!(1)
    reject { |element| elements.include?(element) }
  end

🔎 See on GitHub

in_order_of(key, series)

Returns a new Array where the order has been set to that provided in the series, based on the key of the objects in the original enumerable.

[ Person.find(5), Person.find(3), Person.find(1) ].in_order_of(:id, [ 1, 5, 3 ])
# => [ Person.find(1), Person.find(5), Person.find(3) ]

If the series include keys that have no corresponding element in the Enumerable, these are ignored. If the Enumerable has additional elements that aren’t named in the series, these are not included in the result.

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 196
  def in_order_of(key, series)
    group_by(&key).values_at(*series).flatten(1).compact
  end

🔎 See on GitHub

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"]

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 112
  def including(*elements)
    to_a.including(*elements)
  end

🔎 See on GitHub

index_by()

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

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 ...>, ...}

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 52
  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

🔎 See on GitHub

index_with(default = (no_default = true))

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 }

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 75
  def index_with(default = (no_default = true))
    if block_given?
      result = {}
      each { |elem| result[elem] = yield(elem) }
      result
    elsif no_default
      to_enum(:index_with) { size if respond_to?(:size) }
    else
      result = {}
      each { |elem| result[elem] = default }
      result
    end
  end

🔎 See on GitHub

many?()

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.

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 93
  def many?
    cnt = 0
    if block_given?
      any? do |*args|
        cnt += 1 if yield(*args)
        cnt > 1
      end
    else
      any? { (cnt += 1) > 1 }
    end
  end

🔎 See on GitHub

maximum(key)

Calculates the maximum from the extracted elements.

payments = [Payment.new(5), Payment.new(15), Payment.new(10)]
payments.maximum(:price) # => 15

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 40
  def maximum(key)
    map(&key).max
  end

🔎 See on GitHub

minimum(key)

Calculates the minimum from the extracted elements.

payments = [Payment.new(5), Payment.new(15), Payment.new(10)]
payments.minimum(:price) # => 5

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 32
  def minimum(key)
    map(&key).min
  end

🔎 See on GitHub

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"]

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 161
  def pick(*keys)
    return if none?

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

🔎 See on GitHub

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"]]

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 145
  def pluck(*keys)
    if keys.many?
      map { |element| keys.map { |key| element[key] } }
    else
      key = keys.first
      map { |element| element[key] }
    end
  end

🔎 See on GitHub

sole()

Returns the sole item in the enumerable. If there are no items, or more than one item, raises Enumerable::SoleItemExpectedError.

["x"].sole          # => "x"
Set.new.sole        # => Enumerable::SoleItemExpectedError: no item found
{ a: 1, b: 2 }.sole # => Enumerable::SoleItemExpectedError: multiple items found

📝 Source code

# File activesupport/lib/active_support/core_ext/enumerable.rb, line 206
  def sole
    case count
    when 1   then return first # rubocop:disable Style/RedundantReturn
    when 0   then raise ActiveSupport::EnumerableCoreExt::SoleItemExpectedError, "no item found"
    when 2.. then raise ActiveSupport::EnumerableCoreExt::SoleItemExpectedError, "multiple items found"
    end
  end

🔎 See on GitHub

without(*elements)

Alias for: excluding

Enumerable

Namespace

Class

Methods

Instance Public methods

compact_blank()

exclude?(object)

excluding(*elements)

in_order_of(key, series)

including(*elements)

index_by()

index_with(default = (no_default = true))

many?()

maximum(key)

minimum(key)

pick(*keys)

pluck(*keys)

sole()

without(*elements)