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.
rsort
(PHP 4, PHP 5, PHP 7, PHP 8)
rsort — Ordena um array em ordem descrescente
Descrição
rsort
( array
&$array
, int $sort_flags = ?
) : boolEssa função ordena um array em ordem descrescente (do maior para o menor).
Parâmetros
-
array -
O array de entrada.
-
sort_flags -
Você pode modificar o comportamento da ordenação usando este parâmetro opcional
sort_flags, para detalhes veja a sort().
Valor Retornado
Retorna true em caso de sucesso ou false em caso de falha.
Exemplos
Exemplo #1 Exemplo de rsort()
<?php
$frutas = array ("limao", "laranja", "banana", "maçã");
rsort ($frutas);
foreach( $frutas as $chave => $valor ){
echo "$chave = $valor\n";
}
?>
O exemplo acima irá imprimir:
0 = maçã 1 = limao 2 = laranja 3 = banana
As frutas foram ordenadas em ordem alfabética decrescente.
Notas
Nota: Esta função define novas chaves para os elementos no
array. Ela irá remover quaisquer chaves pré existentes, ao invés de simplesmente reordenar as chaves.
Veja Também
- arsort() - Ordena um array em ordem descrescente mantendo a associação entre índices e valores
- asort() - Ordena um array mantendo a associação entre índices e valores
- ksort() - Ordena um array pelas chaves
- krsort() - Ordena um array pelas chaves em ordem descrescente
- sort() - Ordena um array
- usort() - Ordena um array pelos valores utilizando uma função de comparação definida pelo usuário
add a note
User Contributed Notes 6 notes
ray at non-aol dot com ¶
19 years ago
Alex M ¶
18 years ago
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] $file[1]<br>\n"; #file[0]=Unix timestamp; file[1]=filename
}
?>
slevy1 at pipeline dot com ¶
22 years ago
I thought rsort was working successfully or on a multi-dimensional array of strings that had first been sorted with usort(). But, I noticed today that the array was only partially in descending order. I tried array_reverse on it and that seems to have solved things.
pshirkey at boosthardware dot com ¶
19 years ago
I needed a function that would sort a list of files into reversed order based on their modification date.
Here's what I came up with:
function display_content($dir,$ext){
$f = array();
if (is_dir($dir)) {
if ($dh = opendir($dir)) {
while (($folder = readdir($dh)) !== false) {
if (preg_match("/\s*$ext$/", $folder)) {
$fullpath = "$dir/$folder";
$mtime = filemtime ($fullpath);
$ff = array($mtime => $fullpath);
$f = array_merge($f, $ff);
}
}
rsort($f, SORT_NUMERIC);
while (list($key, $val) = each($f)) {
$fcontents = file($val, "r");
while (list($key, $val) = each($fcontents))
echo "$val\n";
}
}
}
closedir($dh);
}
Call it like so:
display_content("folder","extension");
rnk-php at kleckner dot net ¶
20 years ago
Apparently rsort does not put arrays with one value back to zero. If you have an array like: $tmp = array(9 => 'asdf') and then rsort it, $tmp[0] is empty and $tmp[9] stays as is.
suniafkhami at gmail dot com ¶
10 years ago
If you are sorting an array from a database result set, such as MySQL for example, another approach could be to have your database sort the result set by using ORDER BY DESC, which would be the equivalent of using rsort() on the resulting array in PHP.
[Edited by moderator for clarity: googleguy at php dot net]
