3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr= [ ["test1"=>["a"=>"1"]], ["test2"=>["b"=>"2"]], ["test3"=>["c"=>"3"]], ["test4"=>["d"=>"4"]], ]; $b = call_user_func_array("array_merge",$arr); print_r($b);
Output for 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 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 - 8.1.34, 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 ( [test1] => Array ( [a] => 1 ) [test2] => Array ( [b] => 2 ) [test3] => Array ( [c] => 3 ) [test4] => Array ( [d] => 4 ) )
preferences:
99.11 ms | 2425 KiB | 4 Q