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shuffle> <reset
Last updated: Fri, 13 Nov 2009

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rsort

(PHP 4, PHP 5)

rsort配列を逆順にソートする

説明

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

この関数は、配列を逆順に(高位から低位に)ソートします。

パラメータ

array

入力の配列。

sort_flags

オプションのパラメータ sort_flags によりソートの動作を修正可能です。詳細については、 sort() を参照ください。

返り値

成功した場合に TRUE を、失敗した場合に FALSE を返します。

例1 rsort() の例

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

上の例の出力は以下となります。

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

fruits はアルファベットの逆順にソートされました。

注意

注意: この関数は、 array パラメータの要素に対して新しいキーを割り当てます。 その際、単純にキーを並べ替える代わりに、 すでに割り当てられている既存のキーを削除してしまいます。

参考



shuffle> <reset
Last updated: Fri, 13 Nov 2009
 
add a note add a note User Contributed Notes
rsort
Alex M
28-Jun-2005 02:39
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 09:06
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 03:49
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 07:37
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
13-Jun-2001 06:15
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.

shuffle> <reset
Last updated: Fri, 13 Nov 2009
 
 
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