3v4l.org

run code in 300+ PHP versions simultaneously
<?php $b = [1, 2, 3]; foreach($b ?: [] as &$v){ $v = $v*2; unset($v); } var_dump($b);
Output for 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.31, 8.2.0 - 8.2.26, 8.3.0 - 8.3.14, 8.4.1
array(3) { [0]=> int(1) [1]=> int(2) [2]=> int(3) }
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.40
array(3) { [0]=> int(2) [1]=> int(4) [2]=> int(6) }
preferences:
103.97 ms | 407 KiB | 5 Q