3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $array1 = array('A', 'B'); $array2 = array('1', '2', '3','4'); $num = count($array2); $comb = array(); //The total number of possible combinations $total = pow(2, $num); //Loop through each possible combination for ($i = 0; $i < $total; $i++) { $flag = ''; //For each combination check if each bit is set for ($j = 0; $j < $num; $j++) { //Is bit $j set in $i? if (pow(2, $j) & $i) $flag = $flag.''.$array2[$j]; } if(!empty($flag)) $comb[] = $flag; } $result = array(); foreach($array1 as $val) { foreach($comb as $co) { $result[] = $val."".$co; } } print_r($result);
based on LdNlI
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
Array ( [0] => A1 [1] => A2 [2] => A12 [3] => A3 [4] => A13 [5] => A23 [6] => A123 [7] => A4 [8] => A14 [9] => A24 [10] => A124 [11] => A34 [12] => A134 [13] => A234 [14] => A1234 [15] => B1 [16] => B2 [17] => B12 [18] => B3 [19] => B13 [20] => B23 [21] => B123 [22] => B4 [23] => B14 [24] => B24 [25] => B124 [26] => B34 [27] => B134 [28] => B234 [29] => B1234 )