PHP array_uintersect_uassoc: Compute Array Intersection with Index Checks Using Callback Functions

array_uintersect_uassoc() computes the intersection of arrays while also checking the keys, using user‑supplied callback functions to compare both data and indexes.

Signature:

array array_uintersect_uassoc ( array $array1 , array $array2 , callable $data_compare_func , callable $key_compare_func )

Parameters:

$array1 – The first array.

$array2 – The second array.

$data_compare_func – Callback that returns <0, 0, >0 when the first value is less than, equal to, or greater than the second.

$key_compare_func – Callback that compares the keys.

Return value: An array containing all values that exist in $array1 and also appear in the other arrays, with matching keys according to the callbacks.

Example:

<?php
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "d" => "red");
$array2 = array("a" => "GREEN", "b" => "brown", "c" => "yellow", "d" => "red");
print_r(array_uintersect_uassoc($array1, $array2, "strcasecmp", "strcasecmp"));
?>

Output:

Array
(
    [a] => green
    [b] => brown
)