general question about 'array' functions

Paul_help_

Hi guys.

I have a general question about php's built-in array functions.

There is something I have noticed (correct me if I am wrong).

Is it true that (as a general rule) more likely than not, that php's array functions work mainly on the reference rather than a copy of the array?

Its just that there are so many array functions out there and I just need a general rule I can work with.

Can someone shed some light on this?

ps - and can I ask the same question above in regards to php's built in string functions?

Thanks.

Paul.

NogDog

I don't think there's an overarching rule, it depends on what it's going to do as to whether it makes sense to use a reference or a copy. Just a quick survey of two functions, and the first uses copies of the arrays, while the second modifies via a reference:

From www.php.net/array_merge

array array_merge ( array $array1 [, array $... ] )

From www.php.net/array_walk_recursive

bool array_walk_recursive ( array [B][COLOR="#B22222"]&[/COLOR][/B]$array , callable $callback [, mixed $userdata = NULL ] )
                                  ^
                                  |

So the gist of that is you can always check the documentation when you need to know (and if your editor is really smart, it may show you that, as well).

Bonesnap

The two that always used to confuse me was array_walk() and array_map(). They both essentially do the same thing (iterate over the array and apply a callback function to each element), but the former acts on the array itself whereas the latter returns a new array with each element "processed" by the callback. Like NodDog said, there's no hard rule, though I think the majority of the array_* functions end up returning a new array, but some also return other values (like array_sum(), array_rand(), array_reduce(), array_key_exists(), etc.).