PHP树-不需要递归的实现方法

/** * 创建父节点树形数组 * 参数 * $ar 数组，邻接列表方式组织的数据 * $id 数组中作为主键的下标或关联键名 * $pid 数组中作为父键的下标或关联键名 * 返回 多维数组 **/function find_parent($ar, $id='id', $pid='pid') { foreach($ar as $v) $t[$v[$id]] = $v; foreach ($t as $k => $item){  if( $item[$pid] ){   if( ! isset($t[$item[$pid]]['parent'][$item[$pid]]) )     $t[$item[$id]]['parent'][$item[$pid]] =& $t[$item[$pid]];  } } return $t;}/** * 创建子节点树形数组 * 参数 * $ar 数组，邻接列表方式组织的数据 * $id 数组中作为主键的下标或关联键名 * $pid 数组中作为父键的下标或关联键名 * 返回 多维数组 **/function find_child($ar, $id='id', $pid='pid') { foreach($ar as $v) $t[$v[$id]] = $v; foreach ($t as $k => $item){  if( $item[$pid] ) {   $t[$item[$pid]]['child'][$item[$id]] =& $t[$k];  } } return $t;}  $data = array(   array('ID'=>1, 'PARENT'=>0, 'NAME'=>'祖父'),   array('ID'=>2, 'PARENT'=>1, 'NAME'=>'父亲'),   array('ID'=>3, 'PARENT'=>1, 'NAME'=>'叔伯'),   array('ID'=>4, 'PARENT'=>2, 'NAME'=>'自己'),   array('ID'=>5, 'PARENT'=>4, 'NAME'=>'儿子'),  );  $p = find_parent($data, 'ID', 'PARENT');  $c = find_child($data, 'ID', 'PARENT');  Print_r ($c);

Array(  [1] => Array    (      [ID] => 1      [PARENT] => 0      [NAME] => 祖父      [child] => Array        (          [2] => Array            (              [ID] => 2              [PARENT] => 1              [NAME] => 父亲              [child] => Array                (                  [4] => Array                    (                      [ID] => 4                      [PARENT] => 2                      [NAME] => 自己                      [child] => Array                        (                          [5] => Array                            (                              [ID] => 5                              [PARENT] => 4                              [NAME] => 儿子                            )                        )                    )                )            )          [3] => Array            (              [ID] => 3              [PARENT] => 1              [NAME] => 叔伯            )        )    )  [2] => Array    (      [ID] => 2      [PARENT] => 1      [NAME] => 父亲      [child] => Array        (          [4] => Array            (              [ID] => 4              [PARENT] => 2              [NAME] => 自己              [child] => Array                (                  [5] => Array                    (                      [ID] => 5                      [PARENT] => 4                      [NAME] => 儿子                    )                )            )        )    )  [3] => Array    (      [ID] => 3      [PARENT] => 1      [NAME] => 叔伯    )  [4] => Array    (      [ID] => 4      [PARENT] => 2      [NAME] => 自己      [child] => Array        (          [5] => Array            (              [ID] => 5              [PARENT] => 4              [NAME] => 儿子            )        )    )  [5] => Array    (      [ID] => 5      [PARENT] => 4      [NAME] => 儿子    ))