哪个是更快的array_merge或array_splice来合并数组？

Question

Which is faster array_merge or array_splice to merge arrays? (using array_splice to replace nothing with the 2nd array which has the effect of merging)

array_splice looks like it might use less array copying and as a result it might be faster. Is there any research on this point?

e.g.

array_splice($a1, count($a1), 0, $a2);
$a1 = array_merge($a1, $a2); 

Answer 1

array_merge has to check whether the input array has numeric or named keys, so it knows whether to append or merge. array_splice doesn't need to do this check.