3v4l.org

run code in 300+ PHP versions simultaneously
<?php $l = 'abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-'; $x=0; for ($r=16;$x<$r;$x++) { substr($l,mt_rand(0,strlen($l)-1),1); }

preferences:
32.04 ms | 402 KiB | 5 Q