3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $a = array(1, 2, 3, 4); function transformMe(&$val) { $val *= 2; } array_walk($a, 'transformMe'); var_dump($a);
based on edIIg
Output for 4.3.0 - 7.2.0
array(4) { [0]=> int(2) [1]=> int(4) [2]=> int(6) [3]=> int(8) }