str_shuffle

(PHP 4 >= 4.3.0, PHP 5)

str_shuffle — Randomly shuffles a string

Description

string str_shuffle ( string $str )

str_shuffle() shuffles a string. One permutation of all possible is created.

Parameters

str: The input string.

Return Values

Returns the shuffled string.

Examples

Example #1 str_shuffle() example


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

// This will echo something like: bfdaec
echo $shuffled;
?>


Re: jojersztajner at OXYGEN dot POLAND



"It may be useful if you want to create an accessible CAPTCHA."



This is a flawed concept, since:



1) It's not really accessible -- your scrambled text would produce incomprehensible output if passed through a screen reader (just imagine what a computer saying "uinervtisy" would sound like)



2) It's in no way secure.  A simple script with access to a copy of /usr/dict/words can reduce the space of possible solutions to no more than a handful.



i.e., it's trivial for a script to generate a command like the following, which solves the "uinervtisy" example 100% of the time:



php@server:~$ egrep -i '^u[inervts]{8}y$' /usr/share/dict/words

university

php@server:~$



Novel idea, but it would take a clever spammer all of 5 minutes to defeat it completely.

jojersztajner at OXYGEN dot POLAND
16-Jun-2007 12:27


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.

CygnusX1
14-Feb-2007 10:17


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)

    );

}

?>

dzafel at op dot pl
29-Dec-2006 10:16


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);

}

?>

nmoyroud at teledetection dot fr
03-Nov-2005 01:38


Just another update to password builder function. With this version, you can choose the number of alphanumeric characters to add and the number of non-alphanumeric characters. You obtain a more secure password. You can add another characters to the non-alphanumeric list if you need.

If you want a password with 8 alphanumeric and 3 non-alphanumeric characters in a random order, just call :

random_passwd(8,3);



function generatePasswd($numAlpha=6,$numNonAlpha=2) {

    $pwd = '';

    $listAlpha = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';

    $listNonAlpha = ',;:!?.$/*-+&@_+;./*&?$-!,';



    $start = mt_rand(1, (strlen($listAlpha)-$numAlpha));

    $string = str_shuffle($listAlpha);

    $pwd .= substr($string,$start,$numAlpha);



    $start = mt_rand(1, (strlen($listNonAlpha)-$numNonAlpha));

    $string = str_shuffle($listNonAlpha);

    $pwd .= substr($string,$start,$numNonAlpha);



    return str_shuffle($pwd);

}

support at wiredlabs dot net
15-Aug-2005 11:03


Just an update to sfalcon's function.  Chooses a random number within the length and then selects a random segment not the current segment of 1 to $numchar. Also added upper-case chars.



function random_passwd($numchar=8) {

    $str = "abcefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    $start = mt_rand(1, (strlen($str)-$numchar));

    $string = str_shuffle($str);

    $password = substr($string,$start,$numchar);

    return($password);

}

Qube, Efnet #php
05-Aug-2005 01:20


(correction)

I balked at the loop method used below in inverting and randomising capitalisation and released that we just need to flip the bit (3rd bit or 6th depending on what way you look at it) and it would cause the case change in a character.



Full code and example:

http://www.pgregg.com/projects/php/code/str_case.php

(append an s to the url to get the .phps source)



I came up with a method and thanks to arpad (optimising as ever! :) we now have:



Invert case:

preg_replace('/[a-z]/ie', '\'$0\' ^ str_pad(\'\', strlen(\'$0\'), \' \')', $input);



Randomise case:

preg_replace('/[a-z]/ie', '(rand(0,1) ? \'$0\' ^ str_pad(\'\', strlen(\'$0\'), \' \') : \'$0\')', $input);



and for good measure:

Upper case:

preg_replace('/[a-z]/e', '\'$0\' & str_pad(\'\', strlen(\'$0\'), chr(223))', $input);



Lower case:

preg_replace('/[A-Z]/e', '\'$0\' | str_pad(\'\', strlen(\'$0\'), \' \')', $input);

rudigreen at gmail dot com
02-Jul-2005 04:20


Here are 2 functions, one inverts the case of a string and the other one randomizes the captilization in a string, kinda 

useful string operations.



<?



//Inverts the case of a string

function invert_case($str)

{

    $nstr = '';

    for($i=0;$i<strlen($str);$i++)

    {

        $char = substr($str,$i,1);

        //If it's lower case make it upper case

        if($char == strtolower($char))

        {

            $char = strtoupper($char);

        }

        else //if it's upper than make it lower

        {

            $char = strtolower($char);

        }

        $nstr .= $char;

    }

    return $nstr;

}



//Randomly capilizes/uncaptilizes chars in a string

function rand_case($str)

{

    $nstr = '';

    for($i=0;$i<strlen($str);$i++)

    {

        $char = substr($str,$i,1);

        $char = invert_case($char);

        //2 options, to change or not to change

        rand(0,1) == 1 ? $char = invert_case($char) : null;

        $nstr .= $char;

    }

    return $nstr;

}



//Example:

echo rand_case("pHp rooLz! gUyZ"); //produces something random

echo invert_case("pHP STRiNG sEx");//produces Php strIng SeX

?>

Michiel van den boogaard
17-Jan-2005 11:03


Shortend function for PHP < 4.3

<?php  

function RandomPass($numchar)  

{  

    $word = "a,b,c,d,e,f,g,h,i,j,k,l,m,1,2,3,4,5,6,7,8,9,0";  

    $array=explode(",",$word);  

    shuffle($array);  

    $newstring = implode($array,"");  

    return substr($newstring, 0, $numchar);  

}  

?>

aidan at php dot net
27-Aug-2004 12:31


This functionality is now implemented in the PEAR package PHP_Compat.



More information about using this function without upgrading your version of PHP can be found on the below link:



http://pear.php.net/package/PHP_Compat

sfalcon_(at)_pymesweb_(dot)_com
26-Aug-2004 05:28


You can use str_shuffle to make simple and nice random passwords:



function random_passwd($numchar) {

      $string =str_shuffle("abcefghijklmnopqrstuvwxyz1234567890");

      $password = substr($string,1,$numchar);



      return($password);

}



echo random_passwd('8') // Will return something like "xa3dh214" =)

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str_split

str_rot13

Last updated: Fri, 16 May 2008

str_shuffle

Description

Parameters

Return Values

Examples

See Also