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array_diff_uassoc

(PHP 5, PHP 7, PHP 8)

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

Description

array_diff_uassoc(array $array, array ...$arrays, callable $key_compare_func): array

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

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

Parameters

array

The array to compare from

arrays

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.

callback(mixed $a, mixed $b): int
Caution

Returning non-integer values from the comparison function, such as float, will result in an internal cast to int of the callback's return value. So values such as 0.99 and 0.1 will both be cast to an integer value of 0, which will compare such values as equal.

Return Values

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

Examples

Example #1 array_diff_uassoc() example

In this 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 the key of "red" is automatically assigned to 0 in the first array, whereas it is assigned to 1 in the second array as the key 0 is already taken by yellow.

<?php
function key_compare_func($a, $b)
{
return $a <=> $b;
}

$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.

Notes

Note:

This function only checks one dimension of an n-dimensional array. It is possible to check deeper dimensions by using, for example, array_diff_uassoc($array1[0], $array2[0], "key_compare_func");.

See Also