3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = array(1,2,3,4); foreach($a AS &$y) { $y = $y*2; } echo PHP_EOL; var_dump($a); foreach($a AS $y) { echo $y.' '; } echo PHP_EOL; var_dump($a);

preferences:
38.67 ms | 402 KiB | 5 Q