对数组进展分组

对数组进行分组
我现在想实现这么个功能，
Array ( [tag] => id[type] => complete [level] => 4 [value] => 01 )
Array ( [tag] => name[type] => complete [level] => 4 [value] => 小张 )
Array ( [tag] => flag[type] => complete [level] => 4 )
Array ( [tag] => id [type] => complete [level] => 4 [value] => 02 )
Array ( [tag] => name [type] => complete [level] => 4 [value] => 小李 )
Array ( [tag] => flag [type] => complete [level] => 4 )
Array ( [tag] => id [type] => complete [level] => 4 [value] => 03 )
Array ( [tag] => name [type] => complete [level] => 4 [value] => 小刘 )
Array ( [tag] => flag [type] => complete [level] => 4 )

这几个数组是我通过解析xml文件得到打印出来的，他们每三个数组是一组，我需要把id, name, flag写入数据库，以上这种情况就是写三条数据进数据库。但是我取得的xml文件不固定，内容也不固定，所以每次不一定就是三个一组，我想做个通用的方法，把数组分类，然后循环存入数据库有什么好办法吗？各位大神？
------解决方案--------------------
本帖最后由 xuzuning 于 2014-05-26 17:21:24 编辑

$a = array(
  Array ( 'tag' => 'id',   'type' => 'complete', 'level' => 4, 'value' => '01' ),
  Array ( 'tag' => 'name', 'type' => 'complete', 'level' => 4, 'value' => '小张' ),
  Array ( 'tag' => 'flag', 'type' => 'complete', 'level' => 4, ),
  Array ( 'tag' => 'id',   'type' => 'complete', 'level' => 4, 'value' => '02' ),
  Array ( 'tag' => 'name', 'type' => 'complete', 'level' => 4, 'value' => '小李' ),
  Array ( 'tag' => 'flag', 'type' => 'complete', 'level' => 4, ),
  Array ( 'tag' => 'id',   'type' => 'complete', 'level' => 4, 'value' => '03' ),
  Array ( 'tag' => 'name', 'type' => 'complete', 'level' => 4, 'value' => '小刘' ),
  Array ( 'tag' => 'flag', 'type' => 'complete', 'level' => 4, ),
);

$st = array();
foreach($a as $t) {
  if(isset($st[$t['tag']])) {
    //完成你需要的操作
    $st = array();
  }
  $st[$t['tag']] = $t;
}

应该看得懂吧