3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $array1 = array('A', 'B'); $array2 = array('1', '2', '3'); $num = count($array2); //The total number of possible combinations $total = pow(2, $num); //Loop through each possible combination for ($i = 0; $i < $total; $i++) { $ff=''; //For each combination check if each bit is set for ($j = 0; $j < $num; $j++) { //Is bit $j set in $i? if (pow(2, $j) & $i) $ff = $ff.''.$array2[$j]; } if(!empty($ff)) $temp[] = $ff; } print_r($temp);
based on YfC2v
Output for 4.3.0 - 7.1.0
Array ( [0] => 1 [1] => 2 [2] => 12 [3] => 3 [4] => 13 [5] => 23 [6] => 123 )