3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = [0,0,23,0,0,18,0,0]; $counter = 1; foreach ($arr as &$val){ if($val !== 0){ $val = $counter++; } } print_r($arr);
Output for 5.6.38, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.27, 8.4.1 - 8.4.14
Array ( [0] => 0 [1] => 0 [2] => 1 [3] => 0 [4] => 0 [5] => 2 [6] => 0 [7] => 0 )
preferences:
120.47 ms | 408 KiB | 5 Q