php > print_r(array_merge(['a','b'],['c','d','e','f']));
Array
(
    [0] => a
    [1] => b
    [2] => c
    [3] => d
    [4] => e
    [5] => f
)

php > print_r(['a','b']+['c','d','e','f']);
Array
(
    [0] => a
    [1] => b
    [2] => e
    [3] => f
)