3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array=[[8,9,7],[7,8,9,33,21],[11,12,33,21,9,31]]; $unique=array_unique(array_merge(...$array)); sort($unique); var_export($unique);
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 - 8.1.34, 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 ( 0 => 7, 1 => 8, 2 => 9, 3 => 11, 4 => 12, 5 => 21, 6 => 31, 7 => 33, )
preferences:
80.17 ms | 1529 KiB | 4 Q