3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $a1 = array('A' => 3, 'B' => 4); $a2 = array(); print_r(array_keys($a1)+$a2);
based on Wdep1
Output for 4.3.0 - 7.2.0
Array ( [0] => A [1] => B )