rsort

(PHP 4, PHP 5)

rsort — Trie un tableau en ordre inverse

Description

bool rsort ( array &$array [, int $sort_flags ] )

Effectue un tri en ordre décroissant (du plus grand au plus petit) du tableau array .

Liste de paramètres

array: Le tableau d'entrée.
sort_flags: Vous pouvez modifier le comportement de cette fonction en utilisant le paramètre optionnel sort_flags . Pour plus de détails, voyez le manuel pour la fonction sort().

Valeurs de retour

Cette fonction retourne TRUE en cas de succès, FALSE en cas d'échec.

Exemples

Exemple #1 Exemple avec rsort()


<?php
$fruits = array("lemon", "orange", "banana", "apple");
rsort($fruits);
foreach ($fruits as $key => $val) {
    echo "$key = $val\n";
}
?>

L'exemple ci-dessus va afficher :

0 = orange
1 = lemon
2 = banana
3 = apple

Les fruits ont été classés dans l'ordre alphabétique inverse.

Notes

Note: Cette fonction assigne de nouvelles clés pour les éléments du paramètre array . Elle effacera toutes les clés existantes que vous aviez pu assigner, plutôt que de les trier.

Voir aussi

shuffle

reset

Last updated: Fri, 16 May 2008

add a note User Contributed Notes
rsort

manallesweg at gmx dot de
15-Jan-2008 02:03


I just wrote a little function for sort an array in reverse order WITHOUT pre-ordering the numbers in it..

I hope, someone can use it. ;)



<?php

function rsort_rec($array)

{

    if ( !is_array($array) ) return $array; # return original input when it's not an array

    $c = count($array);

    $c--;

    $j = -1;

    for ( $i = $c; $i > -1; $i-- )

    {

        $array_rec[] = $array[$i];

    }



    return $array_rec;

}



$input = array(167, 20, 100, 205);



print_r(rsort($input)); # printout reordered array with rsort()

# Output: Array ( [0] => 205 [1] => 167 [2] => 100 [3] => 20 )



print_r(rsort_rec($input)); # printout reordered array with rsort_rec()

# Output: Array ( [0] => 205 [1] => 100 [2] => 20 [3] => 167 )

?>

Alex M
27-Jun-2005 07:39


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

   }

?>

pshirkey at boosthardware dot com
14-Jan-2005 01:06


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");

ray at non-aol dot com
02-Nov-2004 07:49


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.

rnk-php at kleckner dot net
17-Jun-2003 12:37


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.

slevy1 at pipeline dot com
12-Jun-2001 11:15


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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Last updated: Fri, 16 May 2008