Online PHP editor | refs for 51UgR

<?php $originalArray = array( array('id' => 1, 'sub-id' => 0), array('id' => 2, 'sub-id' => 0), array('id' => 3, 'sub-id' => 1), array('id' => 4, 'sub-id' => 3), array('id' => 5, 'sub-id' => 4), array('id' => 6, 'sub-id' => 0), array('id' => 7, 'sub-id' => 0), array('id' => 8, 'sub-id' => 6), array('id' => 9, 'sub-id' => 8), array('id' => 10, 'sub-id' => 8) ); foreach ($originalArray as $val) { $array[$val["id"]] = $val; } // we first assign the arrays in a non-destructive way, so that we can easily find the // appropriate key in the array foreach ($array as $key => $val) { if ($val["sub-id"] !== 0) { $array[$val["sub-id"]]["sub"][] = & $array[$key]; } } // remove the ones from the first dimension which are somewhere deeper foreach ($array as $key => $val) { if ($val["sub-id"] !== 0) { unset($array[$key]); } } print_r($array);