【解题】PHP多维数组排序问题

最近在碰PHP，刚好遇到一个问题，涉及到多维数组排序问题。该系列数组都有个关键key PID，要求按照PID将数组重新排列一遍。仅仅排序第一层array即可。使用了array_multisort()，但出现报错。如下：Array
(
    [0] => Array
        (
            [pid] => 0
            [title] => 首页
            [path] => index
            [current] => 0
            [link] => /index.php
        )    [1] => Array
        (
            [tid] => 3
            [pid] => 8
            [mid] => 8
            [topid] => 0
            [upid] => 0
            [exmid] => 0
            [linkid] => 2
            [gotoid] => 17
            [lng] => cn
            [larray] => Array
                (
                    [0] => Array
                        (
                            [tid] => 17
                            [pid] => 50
                            [mid] => 8
                            [topid] => 3
                            [upid] => 3
                        )                    [1] => Array
                        (
                            [tid] => 18
                            [pid] => 50
                            [mid] => 8
                            [topid] => 3
                            [upid] => 3
                        )                    [2] => Array
                        (
                            [tid] => 19
                            [pid] => 50
                            [mid] => 8
                            [topid] => 3
                            [upid] => 3
                        )
                )        )    [2] => Array
        (
            [tid] => 5
            [pid] => 2
            [mid] => 3
            [topid] => 0
            [upid] => 0
            [exmid] => 0
            [larray] => Array
                (
                    [0] => Array
                        (
                            [tid] => 11
                            [pid] => 50
                            [mid] => 3
                            [topid] => 5
                            [upid] => 5
                        )                    [1] => Array
                        (
                            [tid] => 12
                            [pid] => 50
                            [mid] => 3
                            [topid] => 5
                            [upid] => 5
                        )                    [2] => Array
                        (
                            [tid] => 22
                            [pid] => 50
                            [mid] => 8
                            [topid] => 5
                            [upid] => 5
                        )                )        )    [3] => Array
        (
            [tid] => 50
            [pid] => 4
            [mid] => 8
            [topid] => 0
            [upid] => 0
            [larray] => 
        )   )最终结果如下：按照PID从小到大重新排列了一次。Array
(
    [0] => Array
        (
            [pid] => 0
            [title] => 首页
            [path] => index
            [current] => 0
            [link] => /index.php
        )    [1] => Array
        (
            [tid] => 5
            [pid] => 2
            [mid] => 3
            [topid] => 0
            [upid] => 0
            [exmid] => 0
            [larray] => Array
                (
                    [0] => Array
                        (
                            [tid] => 11
                            [pid] => 50
                            [mid] => 3
                            [topid] => 5
                            [upid] => 5
                        )                    [1] => Array
                        (
                            [tid] => 12
                            [pid] => 50
                            [mid] => 3
                            [topid] => 5
                            [upid] => 5
                        )                    [2] => Array
                        (
                            [tid] => 22
                            [pid] => 50
                            [mid] => 8
                            [topid] => 5
                            [upid] => 5
                        )                )        )
    [2] => Array
        (
            [tid] => 50
            [pid] => 4
            [mid] => 8
            [topid] => 0
            [upid] => 0
            [larray] => 
        )    [3] => Array
        (
            [tid] => 3
            [pid] => 8
            [mid] => 8
            [topid] => 0
            [upid] => 0
            [exmid] => 0
            [linkid] => 2
            [gotoid] => 17
            [lng] => cn
            [larray] => Array
                (
                    [0] => Array
                        (
                            [tid] => 17
                            [pid] => 50
                            [mid] => 8
                            [topid] => 3
                            [upid] => 3
                        )                    [1] => Array
                        (
                            [tid] => 18
                            [pid] => 50
                            [mid] => 8
                            [topid] => 3
                            [upid] => 3
                        )                    [2] => Array
                        (
                            [tid] => 19
                            [pid] => 50
                            [mid] => 8
                            [topid] => 3
                            [upid] => 3
                        )
                )        )   )