uksort

(3.0.4 - 3.0.18 only, PHP 4 >= 4.0.0)

uksort --  Sort an array by keys using a user-defined comparison function

Description

void uksort (array array, function cmp_function)

This function will sort the keys of an array using a user-supplied comparison function. If the array you wish to sort needs to be sorted by some non-trivial criteria, you should use this function.

Example 1. uksort() example

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

$a = array (4 => "four", 3 => "three", 20 => "twenty", 10 => "ten");

uksort ($a, "cmp");

while (list ($key, $value) = each ($a)) {
    echo "$key: $value\n";
}

This example would display:

20: twenty
10: ten
4: four
3: three

Note: Instead of a function name, an array containing an object reference and a method name can also be supplied.

See also usort(), uasort(), sort(), asort(), arsort(), ksort(), natsort(), and rsort().