3v4l.org

run code in 500+ PHP versions simultaneously
<?php $arr1 = ['p' => 2, 'pm' => 1]; $arr2 = ['p' => '']; print_r(array_merge($arr1, $arr2));
Output for 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 ( [p] => [pm] => 1 )
preferences:
113 ms | 1571 KiB | 4 Q