在php中将数组的值从低到高排序

Question

  

可能重复：
  How do I sort a multidimensional array in php

我有一个像：

这样的数组

Array
(
    [0] => Array
        (
            [lop] => 7A1
            [tongdiem] => 4
        )

    [1] => Array
        (
            [lop] => 7A2
            [tongdiem] => 5
        )

    [2] => Array
        (
            [lop] => 7A3
            [tongdiem] => 6
        )

    [3] => Array
        (
            [lop] => 7A4
            [tongdiem] => 30
        )

    [4] => Array
        (
            [lop] => 7A5
            [tongdiem] => 21
        )

)

我需要排序[tongdiem] ASC，但不要改变数组键，这就像：

Array
(
    [0] => Array
        (
            [lop] => 7A1
            [tongdiem] => 4
        )

    [1] => Array
        (
            [lop] => 7A2
            [tongdiem] => 5
        )

    [2] => Array
        (
            [lop] => 7A3
            [tongdiem] => 6
        )

    [3] => Array
        (
            [lop] => 7A5
            [tongdiem] => 21
        )

    [4] => Array
        (
            [lop] => 7A4
            [tongdiem] => 30
        )

)

我试过asort，一些php数组内置函数，但没有工作。

我需要使用[tongdiem]值ASC排序数组，但不能更改数组键。

我该怎么办？

Answer 1

http://php.net/manual/en/function.usort.php

function cmp($a, $b) {
    if ($a['tongdiem'] == $b['tongdiem']) {
        return 0;
    }
    return ($a['tongdiem'] < $b['tongdiem']) ? -1 : 1;
}
usort($array, "cmp");