3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = [[0 => 'zero'], [1 => 'one']]; print_r(array_merge(...$a));
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 - 8.1.31, 8.2.0 - 8.2.26, 8.3.0 - 8.3.14, 8.4.1
Array ( [0] => zero [1] => one )
preferences:
84.88 ms | 407 KiB | 5 Q