如何使用 arsort() 在 PHP 中进行稳定排序? [英] How to have a stable sort in PHP with arsort()?

问题描述

我需要在php中根据值对数组进行排序，数组使用一些数字作为键和值，例如:

i need to sort an array in php based on value, array use some numbers for keys and values, for example like this:

$a = array(70 => 1 ,82 => 5  ,61 => 3 ,55 => 1 ,34 => 2 ,53 => 2 ,21 => 4 ,13 => 5);

我喜欢这样排序:

Array
(
    [82] => 5
    [13] => 5
    [21] => 4
    [61] => 3
    [34] => 2
    [53] => 2
    [70] => 1
    [55] => 1
)

我使用了 arsort 并且它工作了，但是有一个问题，因为这个函数将默认排序的 keys 和排序数组更改为:

i used arsort and it worked, but there is a problem because this function make change defult sorted keys and sort array to:

Array
(
    [13] => 5
    [82] => 5
    [21] => 4
    [61] => 3
    [53] => 2
    [34] => 2
    [55] => 1
    [70] => 1
)

推荐答案

构造一个新数组，其元素是原始数组的键、值和位置:

Construct a new array whose elements are the original array's keys, values, and also position:

$temp = array();
$i = 0;
foreach ($array as $key => $value) {
  $temp[] = array($i, $key, $value);
  $i++;
}

然后使用考虑原始位置的用户定义顺序进行排序:

Then sort using a user-defined order that takes the original position into account:

uasort($temp, function($a, $b) {
 return $a[2] == $b[2] ? ($a[0] - $b[0]) : ($a[2] < $b[2] ? 1 : -1);
});

最后，将其转换回原来的关联数组:

Finally, convert it back to the original associative array:

$array = array();
foreach ($temp as $val) {
  $array[$val[1]] = $val[2];
}

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