3v4l.org

run code in 300+ PHP versions simultaneously
<?php $ar = [[1, 2, 3, 4], [1, 2, 3, 4]]; foreach ($ar as &$v) { foreach ($v as $v1) { $v1 = 0; } } unset($v); var_dump($ar);

preferences:
35.71 ms | 402 KiB | 5 Q