array_diff_uassoc

(PHP 5, PHP 7)

Computes the difference of arrays with additional index check which is performed by a user supplied callback function

array array_diff_uassoc ( array $array1, array $array2 [, array $... ], callable $key_compare_func )

Compares array1 against array2 and returns the difference. Unlike array_diff() the array keys are used in the comparison.

Unlike array_diff_assoc() an user supplied callback function is used for the indices comparison, not internal function.

Parameters:

array1

The array to compare from

array2

An array to compare against

...

More arrays to compare against

key_compare_func

The comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.

int callback ( mixed $a, mixed $b )

Returns:

Returns an array containing all the entries from array1 that are not present in any of the other arrays.

Notes:

This function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using, for example, array_diff_uassoc($array1[0], $array2[0], "key_compare_func");.

Examples:

array_diff_uassoc() example

The "a" => "green" pair is present in both arrays and thus it is not in the output from the function. Unlike this, the pair 0 => "red" is in the output because in the second argument "red" has key which is 1.

<?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);
?>

The above example will output:

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

The equality of 2 indices is checked by the user supplied callback function.