按子值对php多维数组进行排序[duplicate]

This question already has an answer here:

这个问题已经有了答案:

• Sort a set of multidimensional arrays by array elements 2 answers
• 根据数组元素2对一组多维数组进行排序

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?

现在我想按[mid]对这个数组进行排序，该怎么做呢?

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

目前我在foreach循环中对它进行排序，必须有更好的方法

EDIT I hoped to output something like

编辑我希望输出一些类似的东西。

[mid] key => array value

[mid] key =>数组值

Thanks

谢谢

3 个解决方案

#1

You can use the usort function.

你可以使用usort函数。

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

See it

看到它

#2

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);
?>

#3

Update

I recently answered this 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.

我最近以一种更有能力的方式回答了这个问题。下面的答案针对的是旧版本的PHP(5.2或更早版本);虽然这个概念是合理的，但是现在有很多更好的方法来做事情。阅读其他问题的答案。

Original (very outdated) answer

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

尤索特就是为了这种情况。如果还需要保留键，则适当的函数是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，如果您不介意的话，您可以正确地声明比较函数:

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

And use it like this:

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。