Finding cartesian product with PHP associative arrays

Question

Say that I have an array like the following:

Array
(
    [arm] => Array
        (
            [0] => A
            [1] => B
            [2] => C
         


        

Answer 1

Here is optimized version of @Jon's cartesian function:

function cartesian($input) {
    $result = array(array());

    foreach ($input as $key => $values) {
        $append = array();

        foreach($result as $product) {
            foreach($values as $item) {
                $product[$key] = $item;
                $append[] = $product;
            }
        }

        $result = $append;
    }

    return $result;
}

Read more about the math behind this algorithm: http://en.wikipedia.org/wiki/Cartesian_product

See more examples of this algorithm in different languages: https://rosettacode.org/wiki/Cartesian_product_of_two_or_more_lists