3v4l.org

run code in 300+ PHP versions simultaneously
<?php $one = array('key'=>'val'); $two = array(0=>array('key1'=>'val1'), 1=>array('key2'=>'val2')); array_unshift($one, $two); var_dump($one + $two);
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
array(3) { [0]=> array(2) { [0]=> array(1) { ["key1"]=> string(4) "val1" } [1]=> array(1) { ["key2"]=> string(4) "val2" } } ["key"]=> string(3) "val" [1]=> array(1) { ["key2"]=> string(4) "val2" } }

preferences:
219.15 ms | 406 KiB | 343 Q