rsort
(PHP 4, PHP 5)
rsort — Sort an array in reverse order
Description
bool rsort
( array
&$array
[, int $sort_flags = SORT_REGULAR
] )This function sorts an array in reverse order (highest to lowest).
Parameters
-
array -
The input array.
-
sort_flags -
You may modify the behavior of the sort using the optional parameter
sort_flags, for details see sort().
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 rsort() example
<?php
$fruits = array("lemon", "orange", "banana", "apple");
rsort($fruits);
foreach ($fruits as $key => $val) {
echo "$key = $val\n";
}
?>
The above example will output:
0 = orange 1 = lemon 2 = banana 3 = apple
The fruits have been sorted in reverse alphabetical order.
Notes
Note: This function assigns new keys to the elements in
array. It will remove any existing keys that may have been assigned, rather than just reordering the keys.
See Also
- arsort() - Sort an array in reverse order and maintain index association
- krsort() - Sort an array by key in reverse order
- The comparison of array sorting functions
- PHP Руководство
- Функции по категориям
- Индекс функций
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- Расширения, относящиеся к переменным и типам
- Массивы
- array_change_key_case
- array_chunk
- array_column
- array_combine
- array_count_values
- array_diff_assoc
- array_diff_key
- array_diff_uassoc
- array_diff_ukey
- array_diff
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- array_fill
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- array_flip
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Коментарии
I thought rsort was working successfully or on a multi-dimensional array of strings that had first been sorted with usort(). But, I noticed today that the array was only partially in descending order. I tried array_reverse on it and that seems to have solved things.Like sort(), rsort() assigns new keys for the elements in array. It will remove any existing keys you may have assigned, rather than just reordering the keys. This means that it will destroy associative keys.
$animals = array("dog"=>"large", "cat"=>"medium", "mouse"=>"small");
print_r($animals);
//Array ( [dog] => large [cat] => medium [mouse] => small )
rsort($animals);
print_r($animals);
//Array ( [0] => small [1] => medium [2] => large )
Use KSORT() or KRSORT() to preserve associative keys.
A cleaner (I think) way to sort a list of files into reversed order based on their modification date.
<?php
$path = $_SERVER[DOCUMENT_ROOT]."/files/";
$dh = @opendir($path);
while (false !== ($file=readdir($dh)))
{
if (substr($file,0,1)!=".")
$files[]=array(filemtime($path.$file),$file); #2-D array
}
closedir($dh);
if ($files)
{
rsort($files); #sorts by filemtime
#done! Show the files sorted by modification date
foreach ($files as $file)
echo "$file[0] $file[1]<br>\n"; #file[0]=Unix timestamp; file[1]=filename
}
?>