3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = Array( Array ( 0 => 'iPhone' ), Array ( 0 => 'iOS' ), Array ( 0 => 'Safari' ) ); $r = array_merge(...$a); print_r($r); echo '----- Using call_user_func_array ----- '; $flat = call_user_func_array('array_merge', array($a)); print_r($r);
Output for 5.6.6, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.27, 8.4.1 - 8.4.14
Array ( [0] => iPhone [1] => iOS [2] => Safari ) ----- Using call_user_func_array ----- Array ( [0] => iPhone [1] => iOS [2] => Safari )

preferences:
137.63 ms | 408 KiB | 5 Q