blocks|key|3220601|text|从+开始，您需要编写自己的函数。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3220602|这似乎做了您想做的事情：http://www.php.net/manual/en/function.usort.php#38827|3220603|3220604|正如手册所说，“如果两个成员进行相等比较，则它们在排序数组中的顺序是未定义的。”这意味着使用的排序不是“稳定的”，并且可能会改变比较相等的元素的顺序。|blockquote|3220605|3220606|有时候你真的需要一个稳定的排序。例如，如果您按一个字段对列表进行排序，然后再按另一个字段对其进行排序，但不希望丢失前一个字段的排序。在这种情况下，最好将usort与考虑两个字段的比较函数一起使用，但如果不能这样做，则使用下面的函数。它是一种合并排序，其复杂度保证为O(n*log(n))，这意味着即使您使用较大的列表(与冒泡排序和插入排序不同，它们的复杂度为O(n%5E2))，它也会保持相当快的速度。|3220607|3220608|<?php
function+mergesort(&$array,+$cmp_function+=+'strcmp')+{
++++//+Arrays+of+size+<+2+require+no+action.
++++if+(count($array)+<+2)+return;
++++//+Split+the+array+in+half
++++$halfway+=+count($array)+/+2;
++++$array1+=+array_slice($array,+0,+$halfway);
++++$array2+=+array_slice($array,+$halfway);
++++//+Recurse+to+sort+the+two+halves
++++mergesort($array1,+$cmp_function);
++++mergesort($array2,+$cmp_function);
++++//+If+all+of+$array1+is+<=+all+of+$array2,+just+append+them.
++++if+(call_user_func($cmp_function,+end($array1),+$array2[0])+<+1)+{
++++++++$array+=+array_merge($array1,+$array2);
++++++++return;
++++}
++++//+Merge+the+two+sorted+arrays+into+a+single+sorted+array
++++$array+=+array();
++++$ptr1+=+$ptr2+=+0;
++++while+($ptr1+<+count($array1)+&&+$ptr2+<+count($array2))+{
++++++++if+(call_user_func($cmp_function,+$array1[$ptr1],+$array2[$ptr2])+<+1)+{
++++++++++++$array[]+=+$array1[$ptr1%2B%2B];
++++++++}
++++++++else+{
++++++++++++$array[]+=+$array2[$ptr2%2B%2B];
++++++++}
++++}
++++//+Merge+the+remainder
++++while+($ptr1+<+count($array1))+$array[]+=+$array1[$ptr1%2B%2B];
++++while+($ptr2+<+count($array2))+$array[]+=+$array2[$ptr2%2B%2B];
++++return;
}
?>|code-block|syntax|javascript|3220609|3220610|此外，您还可以找到++interesting.|3220611|entityMap|0|LINK|mutability|MUTABLE|url|http://www.php.net/manual/en/function.usort.php#38827^0|0|1|2|E|0|C|1H|0|0|0|0|0|0|0|0|0|B|C|0^^$0|@$1|2|3|4|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1A|8|@]|D|@$9|1B|A|1C|1|1D]]|E|$]]|$1|H|3|-4|5|6|7|1E|8|@]|D|@]|E|$]]|$1|I|3|J|5|K|7|1F|8|@]|D|@]|E|$]]|$1|L|3|-4|5|6|7|1G|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|1H|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]|$1|P|3|Q|5|R|7|1J|8|@]|D|@]|E|$S|T]]|$1|U|3|-4|5|6|7|1K|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|1L|8|@$9|1M|A|1N|B|C]]|D|@]|E|$]]|$1|X|3|-4|5|6|7|1O|8|@]|D|@]|E|$]]]|Y|$Z|$5|10|11|12|E|$13|14]]]]

Since <a href="http://bugs.php.net/bug.php?id=53341&amp;edit=1" rel="noreferrer">PHP does not support stable sort after PHP 4.1.0</a>, you need to write your own function.
This seems to do what you're asking: <a href="http://www.php.net/manual/en/function.usort.php#38827" rel="noreferrer">http://www.php.net/manual/en/function.usort.php#38827</a>
<blockquote>
As the manual says, &quot;If two members compare as equal, their order in the sorted array is undefined.&quot; This means that the sort used is not &quot;stable&quot; and may change the order of elements that compare equal.
Sometimes you really do need a stable sort. For example, if you sort a list by one field, then sort it again by another field, but don't want to lose the ordering from the previous field. In that case it is better to use usort with a comparison function that takes both fields into account, but if you can't do that then use the function below. It is a merge sort, which is guaranteed O(n*log(n)) complexity, which means it stays reasonably fast even when you use larger lists (unlike bubblesort and insertion sort, which are O(n^2)).
</blockquote>
<pre><code>&lt;?php
function mergesort(&amp;$array, $cmp_function = 'strcmp') {
 // Arrays of size &lt; 2 require no action.
 if (count($array) &lt; 2) return;
 // Split the array in half
 $halfway = count($array) / 2;
 $array1 = array_slice($array, 0, $halfway);
 $array2 = array_slice($array, $halfway);
 // Recurse to sort the two halves
 mergesort($array1, $cmp_function);
 mergesort($array2, $cmp_function);
 // If all of $array1 is &lt;= all of $array2, just append them.
 if (call_user_func($cmp_function, end($array1), $array2[0]) &lt; 1) {
 $array = array_merge($array1, $array2);
 return;
 }
 // Merge the two sorted arrays into a single sorted array
 $array = array();
 $ptr1 = $ptr2 = 0;
 while ($ptr1 &lt; count($array1) &amp;&amp; $ptr2 &lt; count($array2)) {
 if (call_user_func($cmp_function, $array1[$ptr1], $array2[$ptr2]) &lt; 1) {
 $array[] = $array1[$ptr1++];
 }
 else {
 $array[] = $array2[$ptr2++];
 }
 }
 // Merge the remainder
 while ($ptr1 &lt; count($array1)) $array[] = $array1[$ptr1++];
 while ($ptr2 &lt; count($array2)) $array[] = $array2[$ptr2++];
 return;
}
?&gt;
</code></pre>
<hr />
Also, you may find <a href="http://www.daniweb.com/forums/thread324692.html" rel="noreferrer">this forum thread</a> interesting.

blocks|key|287052|text|为了完整性起见，您还应该查看Schwartzian+transform|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|287053|//+decorate+step
$key+=+0;
foreach+($arr+as+&$item)+{
++++++++$item+=+array($item,+$key%2B%2B);+//+add+array+index+as+secondary+sort+key
}

//+sort+step
asort($arr);+//+sort+it

//+undecorate+step
foreach+($arr+as+&$item)+{
++++$item+=+$item[0];+//+remove+decoration+from+previous+step
}|code-block|syntax|javascript|287054|PHP的默认排序算法可以很好地处理数组，原因如下：|287055|array(1,+0)+<+array(2,+0);+//+true
array(1,+1)+<+array(1,+2);+//+true|287056|如果您想使用自己的排序标准，也可以使用uasort()：|style|CODE|287057|//+each+parameter+is+an+array+with+two+elements
//+[0]+-+the+original+item
//+[1]+-+the+array+key
function+mysort($a,+$b)
{
++++if+($a[0]+!=+$b[0])+{
++++++++return+$a[0]+<+$b[0]+?+-1+:+1;
++++}+else+{
++++++++//+$a[0]+==+$b[0],+sort+on+key
++++++++return+$a[1]+<+$b[1]+?+-1+:+1;+//+ASC
++++}
}|287058|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/Schwartzian_transform^0|E|L|0|0|0|0|0|J|8|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|15|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|16|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|17|8|@$A|18|B|19|O|P]]|9|@]|C|$]]|$1|Q|3|R|5|F|7|1A|8|@]|9|@]|C|$G|H]]|$1|S|3|-4|5|6|7|1B|8|@]|9|@]|C|$]]]|T|$U|$5|V|W|X|C|$Y|Z]]]]

For completeness sake, you should also check out the <a href="http://en.wikipedia.org/wiki/Schwartzian_transform" rel="nofollow">Schwartzian transform</a>:

<pre><code>// decorate step
$key = 0;
foreach ($arr as &amp;$item) {
 $item = array($item, $key++); // add array index as secondary sort key
}

// sort step
asort($arr); // sort it

// undecorate step
foreach ($arr as &amp;$item) {
 $item = $item[0]; // remove decoration from previous step
}
</code></pre>

The default sort algorithm of PHP works fine with arrays, because of this:

<pre><code>array(1, 0) &lt; array(2, 0); // true
array(1, 1) &lt; array(1, 2); // true
</code></pre>

If you want to use your own sorting criteria you can use <code>uasort()</code> as well:

<pre><code>// each parameter is an array with two elements
// [0] - the original item
// [1] - the array key
function mysort($a, $b)
{
 if ($a[0] != $b[0]) {
 return $a[0] &lt; $b[0] ? -1 : 1;
 } else {
 // $a[0] == $b[0], sort on key
 return $a[1] &lt; $b[1] ? -1 : 1; // ASC
 }
}
</code></pre>

blocks|key|288893|text|array_multisort很方便，只需使用一个有序的范围作为第二个数组($order只是临时的，它用于按原始顺序对第一个数组的等价项进行排序)：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|288894|$a+=+[
++"key-0"+=>+5,
++"key-99"+=>+3,
++"key-2"+=>+3,
++"key-3"+=>+7
];

$order+=+range(1,count($a));
array_multisort($a,+SORT_ASC,+$order,+SORT_ASC);

var_dump($a);|code-block|syntax|javascript|288895|输出|BOLD|288896|array(4)+{
++["key-99"]=>
++int(3)
++["key-2"]=>
++int(3)
++["key-0"]=>
++int(5)
++["key-3"]=>
++int(7)
}|288897|我使用带有无序键的测试数据来演示它的工作正常。尽管如此，以下是您的测试脚本的输出：|288898|Array
(
++++[key-1]+=>+10
++++[key-4]+=>+10
++++[key-5]+=>+20
++++[key-8]+=>+20
++++[key-6]+=>+30
++++[key-9]+=>+30
++++[key-2]+=>+40
++++[key-0]+=>+50
++++[key-3]+=>+50
++++[key-7]+=>+50
)|288899|不足之处|288900|它只适用于预定义的比较，您不能使用自己的比较函数。可能的值(array_multisort()的第二个参数)为：|288901|288902|+排序类型标志：|blockquote|288903|288904|288905|288906|SORT_ASC+-+sort+items+ascendingly.|unordered-list-item|288907|SORT_DESC+-+sort+items+descendingly.|288908|SORT_REGULAR+-正常比较项目(不更改types)|288909|SORT_NUMERIC+-+compare+items+numerically|288910|SORT_STRING+-+compare+items+as+strings|288911|SORT_LOCALE_STRING+-根据当前语言环境将项目作为字符串进行比较。它使用区域设置，可以使用setlocale()|288912|SORT_NATURAL更改区域设置-使用natsort()|288913|SORT_FLAG_CASE之类的“自然排序”将项目作为字符串进行比较-可以与SORT_STRING或SORT_NATURAL组合(按位OR)对字符串进行case-insensitively|288914|排序|288915|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/array-multisort^0|0|F|12|6|0|F|0|0|0|0|2|0|0|0|0|0|U|H|0|0|1|6|0|0|0|0|0|8|0|0|9|0|0|C|0|0|C|0|0|B|0|0|I|1H|B|0|0|C|L|9|0|0|E|13|B|1F|C|0|0^^$0|@$1|2|3|4|5|6|7|1V|8|@$9|1W|A|1X|B|C]|$9|1Y|A|1Z|B|C]]|D|@$9|20|A|21|1|22]]|E|$]]|$1|F|3|G|5|H|7|23|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|24|8|@$9|25|A|26|B|M]]|D|@]|E|$]]|$1|N|3|O|5|H|7|27|8|@]|D|@]|E|$I|J]]|$1|P|3|Q|5|6|7|28|8|@]|D|@]|E|$]]|$1|R|3|S|5|H|7|29|8|@]|D|@]|E|$I|J]]|$1|T|3|U|5|6|7|2A|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|2B|8|@$9|2C|A|2D|B|C]]|D|@]|E|$]]|$1|X|3|-4|5|6|7|2E|8|@]|D|@]|E|$]]|$1|Y|3|Z|5|10|7|2F|8|@$9|2G|A|2H|B|M]]|D|@]|E|$]]|$1|11|3|-4|5|6|7|2I|8|@]|D|@]|E|$]]|$1|12|3|-4|5|6|7|2J|8|@]|D|@]|E|$]]|$1|13|3|-4|5|6|7|2K|8|@]|D|@]|E|$]]|$1|14|3|15|5|16|7|2L|8|@$9|2M|A|2N|B|C]]|D|@]|E|$]]|$1|17|3|18|5|16|7|2O|8|@$9|2P|A|2Q|B|C]]|D|@]|E|$]]|$1|19|3|1A|5|16|7|2R|8|@$9|2S|A|2T|B|C]]|D|@]|E|$]]|$1|1B|3|1C|5|16|7|2U|8|@$9|2V|A|2W|B|C]]|D|@]|E|$]]|$1|1D|3|1E|5|16|7|2X|8|@$9|2Y|A|2Z|B|C]]|D|@]|E|$]]|$1|1F|3|1G|5|16|7|30|8|@$9|31|A|32|B|C]|$9|33|A|34|B|C]]|D|@]|E|$]]|$1|1H|3|1I|5|16|7|35|8|@$9|36|A|37|B|C]|$9|38|A|39|B|C]]|D|@]|E|$]]|$1|1J|3|1K|5|16|7|3A|8|@$9|3B|A|3C|B|C]|$9|3D|A|3E|B|C]|$9|3F|A|3G|B|C]]|D|@]|E|$]]|$1|1L|3|1M|5|6|7|3H|8|@]|D|@]|E|$]]|$1|1N|3|-4|5|6|7|3I|8|@]|D|@]|E|$]]]|1O|$1P|$5|1Q|1R|1S|E|$1T|1U]]]]

<a href="http://php.net/array-multisort"><code>array_multisort</code></a> comes in handy, just use an ordered range as second array (<code>$order</code> is just temporary, it serves to order the equivalent items of the first array in its original order):

<pre><code>$a = [
 "key-0" =&gt; 5,
 "key-99" =&gt; 3,
 "key-2" =&gt; 3,
 "key-3" =&gt; 7
];

$order = range(1,count($a));
array_multisort($a, SORT_ASC, $order, SORT_ASC);

var_dump($a);
</code></pre>

Output

<pre><code>array(4) {
 ["key-99"]=&gt;
 int(3)
 ["key-2"]=&gt;
 int(3)
 ["key-0"]=&gt;
 int(5)
 ["key-3"]=&gt;
 int(7)
}
</code></pre>

I used test data with not-ordered keys to demonstrate that it works correctly. Nonetheless, here is the output your test script:

<pre><code>Array
(
 [key-1] =&gt; 10
 [key-4] =&gt; 10
 [key-5] =&gt; 20
 [key-8] =&gt; 20
 [key-6] =&gt; 30
 [key-9] =&gt; 30
 [key-2] =&gt; 40
 [key-0] =&gt; 50
 [key-3] =&gt; 50
 [key-7] =&gt; 50
)
</code></pre>

<h2>Downside</h2>

It only works with predefined comparisons, you cannot use your own comparison function. The possible values (second parameter of <code>array_multisort()</code>) are:

<blockquote>
 Sorting type flags:
 
 <ul>
 <li><code>SORT_ASC</code> - sort items ascendingly.</li>
 <li><code>SORT_DESC</code> - sort items descendingly.</li>
 <li><code>SORT_REGULAR</code> - compare items normally (don't change types)</li>
 <li><code>SORT_NUMERIC</code> - compare items numerically</li>
 <li><code>SORT_STRING</code> - compare items as strings</li>
 <li><code>SORT_LOCALE_STRING</code> - compare items as strings, based on the current locale. It uses the locale, which can be changed using
 <code>setlocale()</code></li>
 <li><code>SORT_NATURAL</code> - compare items as strings using "natural ordering" like <code>natsort()</code></li>
 <li><code>SORT_FLAG_CASE</code> - can be combined (bitwise OR) with <code>SORT_STRING</code> or <code>SORT_NATURAL</code> to sort strings case-insensitively</li>
 </ul>
</blockquote>

blocks|key|289829|text|只是为了用一些非常具体的案例来完成回应。如果$array的数组键是默认的，那么一个简单的array_values(asort($array))就足够了(例如按升序排列)|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|289830|entityMap^0|M|6|18|R|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

Just to complete the responses with some very specific case. If the array keys of <code>$array</code> are the default one, then a simple <code>array_values(asort($array))</code> is sufficient (here for example in ascending order)

blocks|key|3006802|text|为了将来参考，我在Github：https://github.com/vanderlee/PHP-stable-sort-functions上放了一组稳定的内置PHP函数的排序变体，基于@Jack的解决方案和其他一些技巧。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3006803|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/vanderlee/PHP-stable-sort-functions^0|G|1I|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

For future reference, I've put a set of stable sort variants of builtin PHP functions on Github: <a href="https://github.com/vanderlee/PHP-stable-sort-functions" rel="noreferrer">https://github.com/vanderlee/PHP-stable-sort-functions</a>, based on @Jack's solution and a few other tricks.

blocks|key|288937|text|这是一个可以在usort函数中实现稳定排序的解决方案|type|unstyled|depth|inlineStyleRanges|entityRanges|data|288938|public+function+sortBy(array+&$array,+$value_compare_func)
{
++++$index+=+0;
++++foreach+($array+as+&$item)+{
++++++++$item+=+array($index%2B%2B,+$item);
++++}
++++$result+=+usort($array,+function($a,+$b)+use+($value_compare_func)+{
++++++++$result+=+call_user_func($value_compare_func,+$a[1],+$b[1]);
++++++++return+$result+==+0+?+$a[0]+-+$b[0]+:+$result;
++++});
++++foreach+($array+as+&$item)+{
++++++++$item+=+$item[1];
++++}
++++return+$result;
}|code-block|syntax|javascript|288939|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is a solution using which you can achieve stable sort in usort function

<pre><code>public function sortBy(array &amp;$array, $value_compare_func)
{
 $index = 0;
 foreach ($array as &amp;$item) {
 $item = array($index++, $item);
 }
 $result = usort($array, function($a, $b) use ($value_compare_func) {
 $result = call_user_func($value_compare_func, $a[1], $b[1]);
 return $result == 0 ? $a[0] - $b[0] : $result;
 });
 foreach ($array as &amp;$item) {
 $item = $item[1];
 }
 return $result;
}
</code></pre>

blocks|key|287113|text|作为稳定排序的一种解决方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|287114|<?php
header('Content-type:+text/plain');
for+($i+=+0;$i+<+10;$i%2B%2B)
{
++++$arr['key-'+.+$i]+=+rand(1,+5)+*+10;
}
uksort($arr,+function+($a,+$b)+use+($arr)
{
++++if+($arr[$a]+===+$arr[$b])+return+array_search($a,+array_keys($arr))+-+array_search($b,+array_keys($arr));
++++return+$arr[$a]+-+$arr[$b];
});
print_r($arr);|code-block|syntax|javascript|287115|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

As a workaround for stable sort:

<pre class="lang-php prettyprint-override"><code>&lt;?php
header('Content-type: text/plain');
for ($i = 0;$i &lt; 10;$i++)
{
 $arr['key-' . $i] = rand(1, 5) * 10;
}
uksort($arr, function ($a, $b) use ($arr)
{
 if ($arr[$a] === $arr[$b]) return array_search($a, array_keys($arr)) - array_search($b, array_keys($arr));
 return $arr[$a] - $arr[$b];
});
print_r($arr);
</code></pre>

This question is actually inspired from another one here on SO and I wanted to expand it a bit.

Having an associative array in PHP is it possible to sort its values, but where the values are equal to preserve the original key order, using one (or more) of PHP's built in sort function?

Here is a script I used to test possible solutions (haven't found any):

<pre><code>&lt;?php
header('Content-type: text/plain');
for($i=0;$i&lt;10;$i++){
 $arr['key-'.$i] = rand(1,5)*10;
}
uasort($arr, function($a, $b){
 // sort condition may go here //
 // Tried: return ($a == $b)?1:($a - $b); //
 // Tried: return $a &gt;= $b; //
});
print_r($arr);
?&gt;
</code></pre>

Pitfall: Because the keys are ordered in the original array, please don't be tempted to suggest any sorting by key to restore to the original order. I made the example with them ordered to be easier to visually check their order in the output.

Preserve key order (stable sort) when sorting with PHP's uasort

这个问题实际上是从这里的另一个问题中获得的灵感，所以我想稍微扩展一下。在PHP中使用一个(或多个)内置排序函数，在PHP中使用一个(或多个)关联数组可以对其值进行排序吗？以下是我用来测试可能的解决方案的脚本(尚未找到任何解决方案)：<?phpheader('Content-type: text/plain');for(...

问使用PHP的uasort排序时保留键顺序(稳定排序)
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