Online PHP editor | refs for 2FYsV

<?php $sampleData = [ ['group' => 'g1', 'branch' => 'b1', 'unit' => 'null'], ['group' => 'g1', 'branch' => 'b1', 'unit' => 'u2'], ['group' => 'g2', 'branch' => 'null', 'unit' => 'u3'], ['group' => 'g2', 'branch' => 'b6', 'unit' => 'u4'], ['group' => 'g3', 'branch' => 'b7', 'unit' => 'u5'], ]; $groups = []; foreach($sampleData as $row){ $groups[$row['group']][$row['branch']][] = $row['unit']; } var_dump($groups);