PHP array_diff_uassoc() – Compute Array Difference with User-Defined Key Comparison

The PHP function array_diff_uassoc() compares two or more arrays and returns the values from the first array that are not present in any of the other arrays, using both values and keys for comparison, with a user‑defined callback to compare the keys.

Parameters array $array1 – The array to compare. array $array2 – The array to compare against.

... – Additional arrays to compare. callable $key_compare_func – A function that returns <0, 0, >0 when the first key is less than, equal to, or greater than the second key.

Return value

Returns an array containing all entries from $array1 whose keys and values are not present in any of the other arrays.

Example

<?php
function key_compare_func($a, $b) {
    if ($a === $b) {
        return 0;
    }
    return ($a > $b) ? 1 : -1;
}
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "green", "yellow", "red");
$result = array_diff_uassoc($array1, $array2, "key_compare_func");
print_r($result);
?>

Output

Array
(
    [b] => brown
    [c] => blue
    [0] => red
)