根据任何值的计数对数组进行排序答案

【问题标题】：Sort array based on count of any value根据任何值的计数对数组进行排序
【发布时间】：2016-09-21 12:56:23
【问题描述】：

我有一个看起来像的数组

Array
(
    [0] => Array
        (
            [id] => 39662
            [points] => 24
            [subject] => 112
        )

    [1] => Array
        (
            [id] => 39609
            [points] => 24
            [subject] => 87
        )

    [2] => Array
        (
            [id] => 39610
            [points] => 23
            [subject] => 77
        )

    [3] => Array
        (
            [id] => 39608
            [points] => 23
            [subject] => 87
        )

    [4] => Array
        (
            [id] => 39606
            [points] => 22
            [subject] => 60
        )

    [5] => Array
        (
            [id] => 39604
            [points] => 19
            [subject] => 75
        )

    [6] => Array
        (
            [id] => 39595
            [points] => 18
            [subject] => 60
        )

    [7] => Array
        (
            [id] => 39605
            [points] => 18
            [subject] => 47
        )

    [8] => Array
        (
            [id] => 39650
            [points] => 17
            [subject] => 87
        )

    [9] => Array
        (
            [id] => 39660
            [points] => 17
            [subject] => 55
        )

)

现在我想根据关键主题的数量进行排序。您可以看到 subjuet = 87 有 3 条记录，而 subject = 60 有两条记录，因此 87 的所有三个记录都应该首先显示，然后是 60 的记录，然后是其他记录。

我尝试了 array_multisort，但它没有给出预期的结果。

谢谢

【问题讨论】：

给出你试过帮助你的代码
我在 stackoverflow.com/questions/7433569/… 上尝试了代码。 array_multisort 和 usort。
en.wikipedia.org/wiki/Insertion_sort
Sort Multi-dimensional Array by Value的可能重复
@RaviHirani ，我认为您提供的链接没有给出正确的答案。我们必须计算主题运行时间的计数，并根据这些计数对数组进行排序。

标签： php

【解决方案1】：

根据你想要的输出，你只需要array_map()和array_multisort()，

示例：

<?php
// Test Array
$array = array(
    array('id'=>39662,'points'=>'24','subject'=>112),
    array('id'=>39609,'points'=>'24','subject'=>87),
    array('id'=>39610,'points'=>'23','subject'=>77),
    array('id'=>39608,'points'=>'23','subject'=>87),
    array('id'=>39606,'points'=>'22','subject'=>60),
    array('id'=>39604,'points'=>'19','subject'=>75),
    array('id'=>39595,'points'=>'18','subject'=>60),
    array('id'=>39605,'points'=>'18','subject'=>47),
    array('id'=>39650,'points'=>'17','subject'=>87),
    array('id'=>39660,'points'=>'17','subject'=>55),
  );

$newArr = array(); // initialize the new Array
foreach ($array as $key => $value)
{
    $newArr[$value['subject']][] = $value;
}

array_multisort(array_map('count', $newArr), SORT_DESC, $newArr); // using array_multisort() and Sort as DESC order by using array_map()

echo "<pre>";
print_r($newArr);
?>

结果：

Array
(
    [0] => Array
        (
            [0] => Array
                (
                    [id] => 39609
                    [points] => 24
                    [subject] => 87
                )

            [1] => Array
                (
                    [id] => 39608
                    [points] => 23
                    [subject] => 87
                )

            [2] => Array
                (
                    [id] => 39650
                    [points] => 17
                    [subject] => 87
                )

        )

    [1] => Array
        (
            [0] => Array
                (
                    [id] => 39606
                    [points] => 22
                    [subject] => 60
                )

            [1] => Array
                (
                    [id] => 39595
                    [points] => 18
                    [subject] => 60
                )

        )

    [2] => Array
        (
            [0] => Array
                (
                    [id] => 39604
                    [points] => 19
                    [subject] => 75
                )

        )

    [3] => Array
        (
            [0] => Array
                (
                    [id] => 39605
                    [points] => 18
                    [subject] => 47
                )

        )

    [4] => Array
        (
            [0] => Array
                (
                    [id] => 39610
                    [points] => 23
                    [subject] => 77
                )

        )

    [5] => Array
        (
            [0] => Array
                (
                    [id] => 39660
                    [points] => 17
                    [subject] => 55
                )

        )

    [6] => Array
        (
            [0] => Array
                (
                    [id] => 39662
                    [points] => 24
                    [subject] => 112
                )

        )

)

【讨论】：

谢谢@devpro，在上面我只是不需要嵌套数组。元素应根据计数重新排列。
@Rich5757：重新排列

【解决方案2】：

根据您的情况尝试以下方法

$data[] = array('points' => 67, 'subject' => 2);
$data[] = array('points' => 86, 'subject' => 1);
$data[] = array('points' => 85, 'subject' => 6);
$data[] = array('points' => 98, 'subject' => 2);
$data[] = array('points' => 86, 'subject' => 6);
$data[] = array('points' => 67, 'subject' => 7);


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

// Sort the data with volume descending, edition ascending
// Add $data as the last parameter, to sort by the common key
array_multisort($subject, SORT_DESC, $data);

php 手册中我的数组的使用示例。

上面的输出是

Array
(
    [0] => Array
        (
            [points] => 67
            [subject] => 7
        )

    [1] => Array
        (
            [points] => 85
            [subject] => 6
        )

    [2] => Array
        (
            [points] => 86
            [subject] => 6
        )

    [3] => Array
        (
            [points] => 67
            [subject] => 2
        )

    [4] => Array
        (
            [points] => 98
            [subject] => 2
        )

    [5] => Array
        (
            [points] => 86
            [subject] => 1
        )

)

【讨论】：

在您的示例中，因为 subject = 6 有两条记录，因此这些记录应显示在顶部。

【解决方案3】：

function array_sort($array, $key){

    $new_array = array();
    $sortable_array = array();

    if (count($array) > 0) {
        foreach ($array as $k => $v) {
            if (is_array($v)) {
                foreach ($v as $k2 => $v2) {

                    if ($k2 == $key) {
                        $sortable_array[$k] = $v2;
                    }
                }
            } else {
                $sortable_array[$k] = $v;
            }
        }


       asort($sortable_array);


        }

        foreach ($sortable_array as $k => $v) {
            $new_array[$k] = $array[$k];
        }
    }

    return $new_array;
}
 array_sort($a, 'subjects');

//$a 是要排序的数组

【讨论】：