str_shuffle

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

str_shuffle — Embaralha uma string aleatoriamente

Descrição

str_shuffle(string $string): string

str_shuffle() embaralha uma string. Uma permutação de todas as possíveis é criada.

Cuidado

Esta função não gera valores criptograficamente seguros e não deve ser usada para propósitos criptográficos ou fins que exijam que os valores retornados sejam impossíveis de adivinhar.

Se aleatoriedade criptograficamente segura for necessária, a classe Random\Randomizer pode ser usada com o mecanismo Random\Engine\Secure. Para casos de uso simples, as funções random_int() e random_bytes() fornecem uma API conveniente e segura que é garantida pelo CSPRNG do sistema operacional.

Parâmetros

string: A string de entrada.

Valor Retornado

Retorna a string embaralhada.

Registro de Alterações

Versão	Descrição
7.1.0	O algoritmo interno de randomização mudou e agora usa o Gerador de Números Aleatórios » Mersenne Twister em vez da função rand da biblioteca libc.

Exemplos

Exemplo #1 Exemplo de str_shuffle()

<?php
$str = 'abcdef';
$shuffled = str_shuffle($str);

// Isto exibirá algo como: bfdaec
echo $shuffled;
?>

Veja Também

Random\Randomizer::shuffleBytes() - Get a byte-wise permutation of a string
Random\Randomizer::shuffleArray() - Get a permutation of an array

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Notas Enviadas por Usuários (em inglês) 13 notes

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120

jojersztajner at OXYGEN dot POLAND ¶

17 years ago

Aoccdrnig to rseearch at an Elingsh uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is that the frist and lsat ltteer is at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae we do not raed ervey lteter by it slef but the wrod as a wlohe.

Hree's a cdoe taht slerbmcas txet in tihs way:
<?php
    function scramble_word($word) {
        if (strlen($word) < 2)
            return $word;
        else
            return $word{0} . str_shuffle(substr($word, 1, -1)) . $word{strlen($word) - 1};
    }

    echo preg_replace('/(\w+)/e', 'scramble_word("\1")', 'A quick brown fox jumped over the lazy dog.');
?>

It may be ufseul if you wnat to cetare an aessblicce CTCPAHA.

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ronald ¶

9 years ago

This page is missing a very important notice:

Caution

This function does not generate cryptographically secure values, and should not be used for cryptographic purposes. If you need a cryptographically secure value, consider using random_int(), random_bytes(), or openssl_random_pseudo_bytes() instead.

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blamoo2 at hotmail dot com ¶

9 years ago

This function is affected by srand():

<?php
srand(12345);
echo str_shuffle('Randomize me') . '<br/>'; // "demmiezr aon"
echo str_shuffle('Randomize me') . '<br/>'; // "izadmeo rmen"

srand(12345);
echo str_shuffle('Randomize me') . '<br/>'; // "demmiezr aon" again
?>

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ccb2357 at gmail dot com ¶

1 year ago

<?php
    function str_rand(int $length = 20) : string {
        $ascii_codes = range(48, 57) + range(97, 122);
        $codes_lenght = (count($ascii_codes)-1);
        shuffle($ascii_codes);
        $string = '';
        for($i = 1; $i <= $length; $i++){
            $previous_char = $char ?? '';
            $char = chr($ascii_codes[random_int(0, $codes_lenght)]);
            while($char == $previous_char){
                $char = chr($ascii_codes[random_int(0, $codes_lenght)]);
            }
            $string .= $char;
        }
        return str_shuffle($string);
    }
?>

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qeremy [atta] gmail [dotta] com ¶

12 years ago

A proper unicode string shuffle;

<?php
function str_shuffle_unicode($str) {
    $tmp = preg_split("//u", $str, -1, PREG_SPLIT_NO_EMPTY);
    shuffle($tmp);
    return join("", $tmp);
}
?>

$str = "Şeker yârim"; // My sweet love

echo str_shuffle($str); // i�eymrŢekr �

echo str_shuffle_unicode($str); // Şr mreyeikâ

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Anonymous ¶

5 years ago

As noted in this documentation str_shuffle is NOT cryptographically secure, however I have seen many code examples online of people using nothing more than this to generate say random passwords.  So I though I'd share my function which while it makes use of str_shuffle also rely's on random_int() for added security. I use this function to generate salts to use when working with hashes but it can also be used to generate default passwords for new users for example.

It starts with a universe of possible characters, in this case all letters (upper and lower case), 0-9, and several special characters.

It then will run str_shuffle on the universe of characters a random number of times, using random_int() (currently set to 1-10)

Then once the universe of possible characters has been shuffled it using random_int() once more to select the character as a random position within the shuffled string, as does that once for each character you want in the output.

 function secret_gen( $len=64 ) {
    $secret = "";
    $charset = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()_-+=`~,<>.[]: |';
    for ( $x = 1l $x <= random_int( 1, 10 ), $x++ ){
        $charset = str_shuffle( $charset );
    }
    for ( $s = 1; $s <= $len; $s++ ) {
        $secret .= substr( $charset, random_int( 0, 86 ), 1 );
    }
    return $secret;
}

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wmtrader at yandex dot ru ¶

4 years ago

Unshuffle, using:
<?php
$string = "Hello World!";

$seed = 1234567890;
mt_srand($seed);

echo $sh = str_shuffle($string);  //print 'eloWHl rodl!'
echo str_unshuffle($sh, $seed); //print 'Hello World!'
?>

<?php
function str_unshuffle($str, $seed){
    $unique = implode(array_map('chr',range(0,254)));
    $none   = chr(255);
    $slen   = strlen($str);
    $c      = intval(ceil($slen/255));
    $r      = '';
    for($i=0; $i<$c; $i++){
        $aaa = str_repeat($none, $i*255);
        $bbb = (($i+1)<$c) ? $unique : substr($unique, 0, $slen%255);
        $ccc = (($i+1)<$c) ? str_repeat($none, strlen($str)-($i+1)*255) : "";
        $tmp = $aaa.$bbb.$ccc;
        mt_srand($seed);
        $sh  = str_shuffle($tmp);
        for($j=0; $j<strlen($bbb); $j++){
            $r .= $str{strpos($sh, $unique{$j})};
        }
    }
    return $r;
}

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Anonymous ¶

10 years ago

str_shuffle isn't recommendable for passwords. Each character exists only one time).

A function like the following one is better for this.

<?php
    function generatePassword($length = 8) {
        $possibleChars = "abcdefghijklmnopqrstuvwxyz";
        $password = '';

        for($i = 0; $i < $length; $i++) {
            $rand = rand(0, strlen($possibleChars) - 1);
            $password .= substr($possibleChars, $rand, 1);
        }

        return $password;
    }
?>

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CygnusX1 ¶

17 years ago

To cobine functionality and simplicity of the two functions below we can have:

<?php
function generatePasswd($numAlpha=6,$numNonAlpha=2)
{
   $listAlpha = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
   $listNonAlpha = ',;:!?.$/*-+&@_+;./*&?$-!,';
   return str_shuffle(
      substr(str_shuffle($listAlpha),0,$numAlpha) .
      substr(str_shuffle($listNonAlpha),0,$numNonAlpha)
    );
}
?>

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Anonymous ¶

14 years ago

Shuffle for all encoding formats

<?php

function unicode_shuffle($string, $chars, $format = 'UTF-8')
{
    for($i=0; $i<$chars; $i++)
        $rands[$i] = rand(0, mb_strlen($string, $format));
            
        $s = NULL;
            
    foreach($rands as $r)
        $s.= mb_substr($string, $r, 1, $format);
            
    return $s;
}

?>

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kundanborakb at gmail dot com ¶

4 years ago

<?php

//get random string with your desire length

    function getRandom($length){
        
        $str = 'abcdefghijklmnopqrstuvwzyz';
        $str1= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
        $str2= '0123456789';
        $shuffled = str_shuffle($str);
        $shuffled1 = str_shuffle($str1);
        $shuffled2 = str_shuffle($str2);
        $total = $shuffled.$shuffled1.$shuffled2;
        $shuffled3 = str_shuffle($total);
        $result= substr($shuffled3, 0, $length);

        return $result;

    }

    echo getRandom(8);

//output -->
//GATv3JPX
//g7AzhDtR
//DTboKtiL
//CuWZR4cs
//tmTXbzBC

?>

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krzysiekpiasecki at gmail dot com ¶

9 years ago

/**
 * Test shuffleString
 */
function testShuffleString() {
    $shuffled = shuffleString("ĄęźćÓ");
    if (\mb_strlen($shuffled) != 5) {
        throw new \UnexpectedValueException("Invalid count of characters");
    }
    if ($shuffled == "ĄęźćÓ") {
        throw new \UnexpectedValueException("The same string");
    }
    foreach (["Ą", "ę", "ź", "ć", "Ó"] as $char) {
        if (\mb_strpos($shuffled, $char) === false) {
            throw new \UnexpectedValueException("Character not found");
        }
    }
}

/**
 * Shuffle string
 *
 * @param $stringValue String to shuffle
 * @param string $startWith Shuffle $stringValue and append to $startWith
 * @return string Shuffled string
 * @author Krzysztof Piasecki<krzysiekpiasecki@gmail.com>
 */
function shuffleString($stringValue, $startWith = "") {
    $range = \range(0, \mb_strlen($stringValue));
    shuffle($range);
    foreach($range as $index) {
        $startWith .= \mb_substr($stringValue, $index, 1);
    }
    return $startWith;
};

testShuffleString();

echo shuffleString("Hello"); // > 'elHol' (something like this)
echo shuffleString("World!", "Hello "); // > 'Hello do!lrW' (something like this)

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-1

dzafel at op dot pl ¶

17 years ago

Very, very simple random password generator, without using rand() function:

<?php
function random_password($chars = 8) {
   $letters = 'abcefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890';
   return substr(str_shuffle($letters), 0, $chars);
}
?>

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