3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = ['a','b','c','d','e','f']; for($i=count($arr)-1;$i>=0;$i--){ $arr[]=$arr[$i]; unset($arr[$i]); } print_r($arr);
Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 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 ( [6] => f [7] => e [8] => d [9] => c [10] => b [11] => a )
preferences:
131.38 ms | 408 KiB | 5 Q