php generate all combinations from given array

Question

What is the simplest way to convert this PHP array

$a = array(\'A\' => array(1, 2),
           \'B\' => array(3, 4),
           \'C\' =>         


        

Answer 1

You can use this function for this request:

function pc_array_power_set($array) {
    // initialize by adding the empty set
    $results = array(array( ));

    foreach ($array as $element)
        foreach ($results as $combination)
            array_push($results, array_merge(array($element), $combination));

    return $results;
}

Usage:

$set = array('A', 'B', 'C');
$power_set = pc_array_power_set($set);

Output:

array( );
array('A');
array('B');
array('C');
array('A', 'B');
array('A', 'C');
array('B', 'C');
array('A', 'B', 'C');

Resource: http://docstore.mik.ua/orelly/webprog/pcook/ch04_25.htm