3v4l.org

run code in 300+ PHP versions simultaneously
<?php $chars = array(0,1,2,3,4,5,6,7,8,9); $serial = ''; $max = count($chars)-1; for($i=0;$i<20;$i++){ $serial .= (!($i % 5) && $i ? '-' : '').$chars[rand(0, $max)]; }
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.13, 7.3.0 - 7.3.1
preferences:
175.54 ms | 404 KiB | 234 Q