Ruby - Does array A contain all elements of array B [duplicate]

Answer 1

Ruby 2.6+

Ruby's introduced difference in 2.6 for exactly this purpose.

Very fast, very readable, as follows:

a = [1, 2, 3, 4, 5, 6]
b = [1, 2, 3, 4, 5, 6]

a.difference(b).any?
# => false
a.difference(b.reverse).any?
# => false

a = [1, 2, 3, 4, 5, 6]
b = [1, 2, 3]
a.difference(b).any?
# => true

Hope that helps someone!