php 按子值对php多维数组进行排序

Sort php multidimensional array by sub-value

提问by Mr Hyde

I have this array

我有这个数组

Array
(
[data] => Array
    (
        [0] => Array
            (

                [id] => 1293005125
                [viewed] => TRUE
                [active] => TRUE
                [time] => December 22, 2010 13:00 hours
                [timestamp] => 1293006034
                [initial_timestamp] => 1293005125
                [user] => administrator
            )

        [1] => Array
            (

                [mid] => 1293001908
                [viewed] => TRUE
                [active] => TRUE
                [time] => December 22, 2010 13:00 hours
                [timestamp] => 1293001908
                [initial_timestamp] => 1293001908
                [user] => administrator
            )

        [2] => Array
            (

                [mid] => 1293009999
                [viewed] => TRUE
                [active] => TRUE
                [time] => December 22, 2010 13:00 hours
                [timestamp] => 1293009999
                [initial_timestamp] => 1293009999
                [user] => administrator
            )

        [3] => Array
            (

                [mid] => 1293006666
                [viewed] => TRUE
                [active] => TRUE
                [time] => December 22, 2010 13:00 hours
                [timestamp] => 1293006666
                [initial_timestamp] => 1293006666
                [user] => administrator
            )

        [4] => Array
            (

                [mid] => 1293005125
                [viewed] => TRUE
                [active] => TRUE
                [time] => December 22, 2010 13:00 hours
                [timestamp] => 1293006125
                [initial_timestamp] => 1293005125
                [user] => administrator2
            )


    )

Now I would like to sort this array by [mid]How do I do this?

现在我想通过[mid]如何执行此操作对这个数组进行排序？

Currently I sort this in a foreach loop
There has to be a better way

目前我在 foreach 循环中对此进行排序
必须有更好的方法

EDITI hoped to output something like

编辑我希望输出类似

[mid] key => array value

[mid] key => array value

Thanks

谢谢

回答by codaddict

You can use the usortfunction.

您可以使用usort函数。

function cmp($a, $b) {
        return $a["mid"] - $b["mid"];
}
usort($arr, "cmp");

See it

看见

回答by Mukesh Chapagain

The other solution is using array_multisort

另一个解决方案是使用array_multisort

<?php
// Obtain a list of columns
foreach ($data as $key => $row) {
    $mid[$key]  = $row['mid'];
}

// Sort the data with mid descending
// Add $data as the last parameter, to sort by the common key
array_multisort($mid, SORT_DESC, $data);
?>

回答by Jon

Update

更新

I recently answeredthis question in a much more capable manner in the "definitive" topic on sorting multidimensional arrays. The answer below targets old versions of PHP (5.2 and earlier); while the concept is sound, nowadays there are much better ways of doing things. Read the answers on other question instead.

我最近在关于对多维数组进行排序的“确定性”主题中以更有能力的方式回答了这个问题。下面的答案针对旧版本的 PHP（5.2 及更早版本）；虽然这个概念是合理的，但现在有更好的做事方式。请阅读其他问题的答案。

Original (very outdated) answer

原始（非常过时）答案

usortis there for exactly this situation. If you also need keys to be preserved, the appropriate function would be uasort.

usort是不是针对这种情况。如果您还需要保留密钥，则适当的功能是uasort.

For example:

例如：

usort($array, create_function('$a, $b',
   'if ($a["mid"] == $b["mid"]) return 0; return ($a["mid"] < $b["mid"]) ? -1 : 1;'));

Of course if you don't mind, you can declare the comparison function properly:

当然，如果你不介意，你可以正确声明比较函数：

function compareMid($a, $b)
{
    if ($a['mid'] == $b['mid']) {
        return 0;
    }
    return ($a['mid'] < $b['mid']) ? -1 : 1;
}

And use it like this:

并像这样使用它：

usort($array, 'compareMid');

All of this is in the documentation.

所有这些都在文档中。