3v4l.org

run code in 300+ PHP versions simultaneously
<?php $x = [ 'a' => 3, 'b' => 6, ]; $y = [ 'c' => 1, 'd' => 3, 'a' => 1, ]; var_dump($x + $y); var_dump($y + $x);

preferences:
37.46 ms | 402 KiB | 5 Q