Using array_intersect_uassoc() to Compute Array Intersection with Key Comparison in PHP

The array_intersect_uassoc() function in PHP returns an array containing all values from the first array that are present in all other arrays, using both key names and values for comparison.

Function signature:

array_intersect_uassoc(array $array1, array $array2, callable $key_compare_func)

Parameters:

array1 : The first array to compare.

array2 : One or more arrays to compare against the first array.

key_compare_func : A callable that compares keys; it must return an integer less than, equal to, or greater than zero when the first key is respectively less than, equal to, or greater than the second.

Return value: An array containing the intersection of the arrays, where both keys and values match across the compared arrays.

Example usage:

<?php
$array1 = array(
    "a" => "green",
    "b" => "brown",
    "c" => "blue",
    "d" => "red"
);

$array2 = array(
    "a" => "GREEN",
    "b" => "brown",
    "e" => "yellow",
    "f" => "red"
);

print_r(array_intersect_uassoc($array1, $array2, "strcasecmp"));
?>

Output:

Array
(
    [b] => brown
)