Online PHP editor | refs for d03AW

<?php $muLevelIds = []; $subjectLevelIds = [1,6,7,8]; $occLevelIds = [6,7]; var_dump(array_union($muLevelIds, $subjectLevelIds, $occLevelIds)); function array_union($muLevelIds, $subjectLevelIds, $occLevelIds) { $allLevelIds = [1,6,7,8,9]; $combined = (array_intersect($muLevelIds, $subjectLevelIds, $occLevelIds)); return array_intersect($allLevelIds, $combined); }