php - 合并多维数组

Question

我在 PHP 中有一个具有这种结构的数组：

Array
(
  [7] => Array
    (
      [6] => Array
        (
          [200000000] => Array
            (
              [201000001] => Array
                (
                  [201000002] => Entry
                  [201000003] => History
                  [201000004] => Statistic
                  [201000005] => Edit
                )

            )

        )

      [7] => Array
        (
          [200000000] => Array
            (
              [201000001] => Array
                (
                  [201000002] => Entry
                  [201000005] => Edit
                )

              [201000006] => Request
              [201000007] => Array
                (
                  [201000008] => Array
                    (
                      [201000009] => Inbox
                      [201000010] => Cancellation
                    )

                )

            )

        )

    )

)

我怎样才能把这个数组变成这样的东西：

Array
(
  [7] => Array
    (
      [6] => Array
        (
          [200000000] => Array
            (
              [201000001] => Array
                (
                  [201000002] => Entry
                  [201000003] => History
                  [201000004] => Statistic
                  [201000005] => Edit
                )

              [201000006] => Request
              [201000007] => Array
                (
                  [201000008] => Array
                    (
                      [201000009] => Inbox
                      [201000010] => Cancellation
                    )
                )
            )
        )
    )
)

如果有 PHP 内置函数可以做到这一点，那更好？或者也许是一个没有太多循环的函数？

之前谢谢...