3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = [ '1', '2', '3', '4', ]; foreach ($arr as &$v) { $v++; } foreach ($arr as $v) { $v++; } print_r($arr);
Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 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 - 8.4.18, 8.5.0 - 8.5.3
Array ( [0] => 2 [1] => 3 [2] => 4 [3] => 6 )
preferences:
106.47 ms | 1936 KiB | 4 Q