array_udiff_assoc in PHP

Syntax of array_udiff_assoc

array array_udiff_assoc(array array1, array array2
[, … array arrayN], string function)

Returns an array containing all the values in array1 that are not present in any of the other arrays. Both keys and values are used to check for equality; that is, “a” => 1 and “b” => 1 are not considered equal. The function function is used to compare the values of the elements for equality. The function is called with two parameters—the values to compare. It should return an integer less than 0 if the first argument is less than the second, 0 if the first and second arguments are equal, and an integer greater than 0 if the first argument is greater than the second. The keys of the values are preserved.

Example of array_udiff_assoc

<?php
class cr {
    private $priv_member;
    function cr($val)
    {
        $this->priv_member = $val;
    }

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

$a = array("0.1" => new cr(9), "0.5" => new cr(12), 0 => new cr(23), 1=> new cr(4), 2 => new cr(-15),);
$b = array("0.2" => new cr(9), "0.5" => new cr(22), 0 => new cr(3), 1=> new cr(4), 2 => new cr(-15),);

$result = array_udiff_assoc($a, $b, array("cr", "comp_func_cr"));
print_r($result);
?>

Array
(
    [0.1] => cr Object
        (
            [priv_member:private] => 9
        )

    [0.5] => cr Object
        (
            [priv_member:private] => 12
        )

    [0] => cr Object
        (
            [priv_member:private] => 23
        )
)