- var_dump: documentation ( source)
- array_merge: documentation ( source)
<?php
$configIds = [3];
$more = [3,2,1];
$groupd = [1,2];
var_dump(array_merge($configIds,$groupd));
var_dump(array_merge($more,$groupd));
var_dump($configIds+$groupd, $more+$groupd);