PHP: Get all combinations of multiple arrays (preserves keys)

get_combinations.php

<?php

function get_combinations($arrays) {
	$result = [[]];
	foreach ($arrays as $property => $property_values) {
		$tmp = [];
		foreach ($result as $result_item) {
			foreach ($property_values as $property_value) {
				$tmp[] = array_merge($result_item, array($property => $property_value));
			}
		}
		$result = $tmp;
	}
	return $result;
}

$combinations = get_combinations(
	[
		'item1' => ['A', 'B'],
		'item2' => ['C', 'D'],
		'item3' => ['E', 'F'],
	]
);

print_r($combinations); // 2*2*2 = 8

output.txt

Array
(
    [0] => Array
        (
            [item1] => A
            [item2] => C
            [item3] => E
        )

    [1] => Array
        (
            [item1] => A
            [item2] => C
            [item3] => F
        )

    [2] => Array
        (
            [item1] => A
            [item2] => D
            [item3] => E
        )

    [3] => Array
        (
            [item1] => A
            [item2] => D
            [item3] => F
        )

    [4] => Array
        (
            [item1] => B
            [item2] => C
            [item3] => E
        )

    [5] => Array
        (
            [item1] => B
            [item2] => C
            [item3] => F
        )

    [6] => Array
        (
            [item1] => B
            [item2] => D
            [item3] => E
        )

    [7] => Array
        (
            [item1] => B
            [item2] => D
            [item3] => F
        )
)