Generating pseudo random alpha-numeric strings

Question

How can I generate a  pseudo random alpha-numeric string  something like   d79jd8c  in PHP

User · Answer

Generate cryptographically strong  random  potentially  8-character string using the openssl random pseudo bytes function   echo bin2hex openssl random pseudo bytes 4      Procedural way   function randomString int  length   string       return bin2hex openssl random pseudo bytes  length        Update   PHP7 introduced the random x   functions which should be even better  If you come from PHP 5 X  use excellent paragonie random compat library which is a polyfill for random bytes   and random int   from PHP 7   function randomString  length        return bin2hex random bytes  length

User · Answer

One line solution   echo substr  str shuffle  str repeat   abcdefghijklmnopqrstuvwxyz0123456789   10      0  7      You can change the substr parameter in order to set a different length for your string

User · Answer

I have made the following quick function just to play around with the range   function  It just might help someone sometime   Function pseudostring  length   50            Generate arrays with characters and numbers      lowerAlpha   range  a    z         upperAlpha   range  A    Z         numeric   range  0    9            Merge the arrays      workArray   array merge  numeric  array merge  lowerAlpha   upperAlpha         returnString               Add random characters from the created array to a string     for   i   0   i  lt   length   i               character    workArray rand 0  61             returnString     character             return  returnString

User · Answer

First list the desired characters   chars    0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ     Use the str shuffle  string  function  This function will provide you a randomly shuffled string    alpha substr str shuffle  chars   0  50     50 is the Length of string

User · Answer

Use the ASCII table to pick a range of letters  where the   range start    range end is a value from the decimal column in the ASCII table   I find that this method is nicer compared to the method described where the range of characters is specifically defined within another string      range is numbers  48  through capital and lower case letters  122   range start   48   range end     122   random string        random string length   10   for   i   0   i  lt   random string length   i         ascii no   round  mt rand   range start    range end         generates a number within the range      finds the character represented by  ascii no and adds it to the random string      study   chr   function for a better understanding    random string    chr   ascii no       echo  random string    See More    chr function mt rand function

User · Answer

public function randomString  length   8         characters   implode            ABCDEFGHIJKLMNOPORRQSTUWVXYZ            abcdefghijklmnoprqstuwvxyz            0123456789                     amp                   charactersLength   strlen  characters  - 1       string                      while   length             string     characters mt rand 0   charactersLength            -- length             return  string

User · Answer

You can use the following code  It is similar to existing functions except that you can force special character count  function random string            8 characters  7 lower-case alphabets and 1 digit      character sets               quot count quot    gt  7   quot characters quot    gt   quot abcdefghijklmnopqrstuvwxyz quot              quot count quot    gt  1   quot characters quot    gt   quot 0123456789 quot               temp array   array        foreach   character sets as  character set            for   i   0   i  lt   character set  quot count quot     i                   random   random int 0  strlen  character set  quot characters quot    - 1                temp array      character set  quot characters quot    random                       shuffle  temp array       return implode  quot  quot    temp array

User · Answer

I like this function for the job  function randomKey  length         pool   array merge range 0 9   range  a    z   range  A    Z          for  i 0   i  lt   length   i               key     pool mt rand 0  count  pool  - 1              return  key     echo randomKey 20

User · Answer

If you want a very easy way to do this  you can lean on existing PHP functions  This is the code I use   substr  sha1  time      0  15    time   gives you the current time in seconds since epoch  sha1   encrypts it to a string of 0-9a-f  and substr   lets you choose a length  You don t have to start at character 0  and whatever the difference is between the two numbers will be the length of the string

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The modern way to do that with type hint   rand int for real randomeness   function random string int  size   string        characters   array merge          range 0  9           range  A    Z                string            max   count  characters  - 1      for   i   0   i  lt   size   i               string     characters random int 0   max               return  string

User · Answer

1 line    FROM   0   TO    zzzz    code   base convert rand   FROM  base convert   TO   36 10   10 36   echo  code

User · Answer

function generateRandomString  length   10         characters    0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ        charactersLength   strlen  characters        randomString           for   i   0   i  lt   length   i               randomString     characters rand 0   charactersLength - 1              return  randomString    echo generateRandomString

User · Answer

I know it s an old post but I d like to contribute with a class I ve created based on Jeremy Ruten s answer and improved with suggestions in comments       class RandomString             private static  characters    abcdefghijklmnopqrstuvwxyz0123456789         private static  string        private static  length   8    default random string length        public static function generate  length   null                   if  length             self   length    length                      characters length   strlen self   characters  - 1           for   i   0   i  lt  self   length   i                self   string    self   characters mt rand 0   characters length                       return self   string

User · Answer

First make a string with all your possible characters     characters    abcdefghijklmnopqrstuvwxyz0123456789     You could also use range   to do this more quickly   Then  in a loop  choose a random number and use it as the index to the  characters string to get a random character  and append it to your string     string         max   strlen  characters  - 1   for   i   0   i  lt   random string length   i             string     characters mt rand 0   max          random string length is the length of the random string

User · Answer

This is something I use    cryptoStrong   true     can be false  length   16     Any length you want  bytes   openssl random pseudo bytes  length   cryptoStrong    randomString   bin2hex  bytes     You can see the Docs for openssl random pseudo bytes here  and the Docs for bin2hex here

User · Answer

Jeremy s answer is great  If  like me  you re unsure of how to implement range    you can see my version using range      lt  php  character array   array merge range  a    z    range 0  9     string           for  i   0   i  lt  6   i               string     character array rand 0   count  character array  - 1           echo  string    gt    This does the exact same thing as Jeremy s but uses merged arrays where he uses a string  and uses count   where he uses strlen

User · Answer

Maybe I missed something here  but here s a way using the uniqid   function

User · Answer

Simple guys      but remember each byte is random between 0 and 255 which for a random string will be fine   Also remember you ll have two characters to represent each byte    str   bin2hex random bytes 32        64 character string returned

[php] Generating (pseudo)random alpha-numeric strings

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