1.
【案例】如下数组，要将最底层的数组为空的去掉
Array
(
    [tech] => Array
        (
            [Article] => Array
                (
                    [0] => AdminForm
                    [1] => AdminSave
                    [2] => AdminList
                    [3] => AdminMultiDeal
                )

            [VoteOption] => 
           
    [www] => Array
        (
            [Home] => 
        )


)
转为：
Array
(
    [tech] => Array
        (
            [Article] => Array
                (
                    [0] => AdminForm
                    [1] => AdminSave
                    [2] => AdminList
                    [3] => AdminMultiDeal
                )

)

【思路：】
foreach ($mca as $k1 => $v1) {            
            foreach ($v1 as $k2 => $v2) {
                if(!empty($v2)) {
                    $newMca[$k1][$k2] = $v2; //只得到具有admin的action的MCA
                 }
            }
        }