3v4l.org

run code in 500+ PHP versions simultaneously
<?php $d = 201511; $year = substr($d,0,4); $month = substr($d,-2); $reverse = $month.$year; echo $reverse;
Output for 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.22, 8.5.0 - 8.5.7
112015
preferences:
110.36 ms | 1420 KiB | 4 Q