rsort

(PHP 4, PHP 5, PHP 7, PHP 8)

rsort — Ordina un array in ordine decrescente

Descrizione

rsort(array $array, int $sort_flags = ?): bool

Questa funzione ordina un array in ordine decrescente.

Restituisce true in caso di successo, false in caso di fallimento.

Example #1 esempio di rsort()

<?php
$frutti = array("limone", "arancia", "banana", "mela");
rsort($frutti);
reset($frutti);
while (list($chiave, $valore) = each($frutti)) {
    echo "$chiave = $valore\n";
}
?>

Questo esempio mostrerà:

0 = mela
1 = limone
2 = banana
3 = arancia

I frutti sono stati ordinati in ordine alfabetico decrescente.

Si può modificare il comportamento dell'ordinamento usando il parametro opzionale sort_flags, per maggiori dettagli vedere sort().

Vedere anche arsort(), asort(), ksort(), sort() e usort().

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User Contributed Notes 3 notes

down

Alex M ¶

19 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
   }
?>

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ray at non-aol dot com ¶

19 years ago

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.

down

-4

slevy1 at pipeline dot com ¶

23 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.

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