Question

Just wondering about the performance impact of copying very large php variables. For example say $arr is an enormous array. If I do $arr2 = $arr, is this a deep copy or is $arr2 merely a pointer to $arr like it is in Java? Thanks in advance.

Answer 1

$arr2 = $arr creates a deep copy. But the actual copying only happens when $arr2 is modified — PHP utilizes copy-on-write.

If you want a “pointer” instead of a copy, use $arr2 =& $arr, which makes $arr2 a reference to $arr.