str_shuffle

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

str_shuffle — Mischt einen String nach dem Zufallsprinzip

Beschreibung

str_shuffle(string $string): string

str_shuffle() mischt eine Zeichenkette. Es entsteht eine Permutation aller vorhandenen Zeichen.

Achtung

Diese Funktion erzeugt keine kryptografisch sicheren Werte und darf nicht für kryptografische Zwecke verwendet werden oder für Zwecke, bei denen die zurückgegebenen Werte nicht abschätzbar sein dürfen.

Falls kryptographisch sichere Zufallszahlen benötigt werden, kann der Random\Randomizer mit der Random\Engine\Secure-Engine verwendet werden. Für einfache Anwendungsfälle bieten die Funktionen random_int() und random_bytes() eine bequeme und sichere API, die den CSPRNG des Betriebssystems verwendet.

Parameter-Liste

string: Die Eingabezeichenkette.

Rückgabewerte

Gibt die vermischte Zeichenkette zurück.

Changelog

Version	Beschreibung
7.1.0	Der interne Zufallsalgorithmus wurde geändert, und verwendet nun den » Mersenne Twister Zufallszahlengenerator statt der rand Funktion von libc.

Beispiele

Beispiel #1 str_shuffle()-Beispiel

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

// erzeugt eine Ausgabe wie: bfdaec
echo $shuffled;
?>

Siehe auch

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

Improve This Page

Learn How To Improve This Page • Submit a Pull Request • Report a Bug

＋add a note

User Contributed Notes 13 notes

down

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.

down

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.

down

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
?>

down

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);
    }
?>

down

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

down

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;
}

down

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;
}

down

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;
    }
?>

down

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)
    );
}
?>

down

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;
}

?>

down

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

?>

down

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)

down

-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);
}
?>

＋add a note