Module: Enumerable

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 }

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

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}

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, unless the filter option is set to false.

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"]

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 ...>, ...}

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 }

Calculates the maximum from the extracted elements.

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

Calculates the minimum from the extracted elements.

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

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"]

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"]]

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

Alias for #excluding.