array_intersect_ukey

(PHP 5 >= 5.1.0, PHP 7)

Computes the intersection of arrays using a callback function on the keys for comparison

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

array_intersect_ukey() returns an array containing all the values of array1 which have matching keys that are present in all the arguments.

Parameters:

array1

Initial array for comparison of the arrays.

array2

First array to compare keys against.

...

Variable list of array arguments to compare keys 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 the values of array1 whose keys exist in all the arguments.

Examples:

array_intersect_ukey() example

<?php
function key_compare_func($key1, $key2)
{
    if ($key1 == $key2)
        return 0;
    else if ($key1 > $key2)
        return 1;
    else
        return -1;
}

$array1 = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan'   => 8);

var_dump(array_intersect_ukey($array1, $array2, 'key_compare_func'));
?>

The above example will output:

array(2) {
  ["blue"]=>
  int(1)
  ["green"]=>
  int(3)
}