如何删除基于键的数组元素？

可能的重复：
如何从php中的数组中删除元素？

例如

Array(      
    [0] => Array
        (
            [0] => hello
            [1] => open
        )

    [1] => Array
        (
            [0] => good
            [1] => center
        )

    [2] => Array
        (
            [0] => hello
            [1] => close
        )
)

我想删除键为1的元素，在操作之后：

Array(
    [0] => Array
        (
            [0] => hello
            [1] => open
        )

    [2] => Array
        (
            [0] => hello
            [1] => close
        )
)