What is the practical use of array_diff_uassoc?

Question

array_diff_assoc and array_diff_uassoc both do the same thing (compute difference b/w array with additinal index check) the only difference is the later one accpet a callback.

The difference is just callback, In which case you should prefer array_diff_uassoc instead of array_diff_assoc.

I want to understand that If the callback is going to do the same as below is every case then what is the use of array_diff_uassoc

function key_compare_func($a, $b)
{
    if ($a === $b) {
        return 0;
    }
    return ($a > $b)? 1:-1;
}

Did you ask a question in the title and then answer it in the question contents? — Explosion Pills, Jan 22 '13 at 16:50
"Is that how we get ants Other Barry? Yes Other Barry, that is exactly how we get ants." — Sammitch, Jan 22 '13 at 16:54
the callback isnt going to be what you posted, and if it is, you are doing it wrong — Ascherer, Jan 22 '13 at 16:55
Duplicate: http://stackoverflow.com/questions/9117058/what-is-the-difference-between-array-udiff-assoc-and-array-diff-uassoc — Ascherer, Jan 22 '13 at 16:57
@Ascherer: Not the duplicate one. People you are very quick to close the question. Just understand the question I can understand the question and the question is still a good one. Thanks — Daric, Jan 22 '13 at 17:02

Sammitch · Accepted Answer · 2016-02-29T19:51:41.027

The practical difference is that the user-defined function can be anything other than the default. You define the callback yourself.

Just because the documentation only gives a simple example doesn't mean that that is the only possibility. Here is a contrived example of a callback function you'd use tom compare elements in a multi-dimensional array:

function key_compare_func($a, $b) {
    if ($a['key']['subkey'] === $b['key']['subkey']) {
        return 0;
    }
    return ($a['key']['subkey'] > $b['key']['subkey'])? 1:-1;
}

Edit: PHP7 has spaceships!

function key_compare_func($a, $b) {
    return $a['key']['subkey'] <=> $b['key']['subkey']
}

What is the practical use of array_diff_uassoc?

1 Answers1