Online PHP editor | refs for vm6PF

<?php /* assuming top level pid = 0 */$rows = array ( array ( 'id' => 1, 'pid' => 0 ), array ( 'id' => 2, 'pid' => 1 ), array ( 'id' => 3, 'pid' => 2 ), array ( 'id' => 4, 'pid' => 0 ), array ( 'id' => 5, 'pid' => 4 ), /* ... */);$rows = array_column ( $rows, null, 'id' );foreach ( $rows as $key => $val ) { if ( $val ['pid'] ) { if ( isset ( $rows [$val ['pid']] )) { $rows [$val ['pid']]['children'][] = &$rows [$key]; } }}foreach ( $rows as $key => $val ) { if ( $val ['pid'] ) unset ( $rows [$key] );}var_dump ( $rows );