php怎么读一个多维数据动态的

php如何读一个多维数据动态的、
Array
(
    [3] => Array
        (
            [0] => Array
                (
                    [seconds] => 16930
                    [no] => 0
                    [pt] => 3
                    [k] => 119981343
                    [size] => 906330
                )

        )

    [2] => Array
        (
            [0] => Array
                (
                    [seconds] => 16930
                    [no] => 0
                    [pt] => 2
                    [k] => 119980914
                    [size] => 472101
                )

        )

    [4] => Array
        (
            [0] => Array
                (
                    [seconds] => 16930
                    [no] => 0
                    [pt] => 4
                    [k] => 119981696
                    [size] => 1735787
                )

        )

    [99] => Array
        (
            [0] => Array
                (
                    [seconds] => 16930
                    [no] => 0
                    [pt] => 99
                    [k] => 119981988
                    [size] => 679868
                )

        )

)



我如何读到其内的值，就是no pt k size
这是一个动态数据，就是说3,2,4,99不是固定的，因此不能用此法：[4][0][no]
应该怎么办啊？
------解决方案--------------------

foreach($ar as $r) {<br />  echo $r[0]['k'];<br />}