/ Ruby
/
method

flatten

v1_8_6_287 - Show latest stable - Class: Array
flatten()
public

Returns a new array that is a one-dimensional flattening of this array (recursively). That is, for every element that is an array, extract its elements into the new array. 

   s = [ 1, 2, 3 ]           #=> [1, 2, 3]
   t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
   a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
   a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10

1Note

Make your custom enumerable "flattenable"

stevo ยท May 5, 2020

Just alias +to_a+ to +to_ary+

class A
include Enumerable

def each
  yield "a"
  yield "b"
end
end


[A.new, A.new].flatten => [#<A:0x00007fbddf1b5d88>, #<A:0x00007fbddf1b5d60>]


class A
def to_ary
  to_a
end
end

[A.new, A.new].flatten => ["a", "b", "a", "b"]