Array
difference([2,3,4,5], [1,2,3,4]) => [5, 1] ;difference([1,2,3,4], [2,3,4,5]) => [1, 5];difference([1,2,3,4], [1,2,3,4]) => [];difference([1,2,3,4], []) => [1, 2, 3, 4] Copy
difference([2,3,4,5], [1,2,3,4]) => [5, 1] ;difference([1,2,3,4], [2,3,4,5]) => [1, 5];difference([1,2,3,4], [1,2,3,4]) => [];difference([1,2,3,4], []) => [1, 2, 3, 4]