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    rsort

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

    rsort — Ordena um array em ordem descrescente

    Descrição

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

    Essa 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 produzirá:

    0 = maçã
1 = limao
2 = laranja
3 = banana

    As frutas foram ordenadas em ordem alfabética decrescente.

    Notas

    Nota: Esta função atribui novas chaves aos elementos do array. Ela removerá todas as chaves existentes que possam ter sido atribuídas, em vez de apenas 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 em ordem ascendente
    • usort() - Ordena um array pelos valores utilizando uma função de comparação definida pelo usuário

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    User Contributed Notes 6 notes

    up
    1
    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
    }
    ?>
    up
    0
    ray at non-aol dot com
    18 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.
    up
    -4
    pshirkey at boosthardware dot com
    18 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");
    up
    -5
    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.
    up
    -8
    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.
    up
    -11
    suniafkhami at gmail dot com
    9 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]
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