note 56246 deleted from function.rand by felipe

Note Submitter: andy at andycc dot net 

----

Need a string of random letters and numbers for a primary key/session ID?  
Here's a dead simple function that works pretty efficiently.

Set $template to a string of letters/numbers to choose from
(e.g. any of the letters in this string can be returned as part of the unique ID - could use symbols etc.)

Then call GetRandomString(?) with an integer value that defines how long you want the string to be.

<?php

// Andy Shellam, andy [at] andycc [dot] net

// generate a random string of numbers/letters

settype($template, "string");

// you could repeat the alphabet to get more randomness
$template = "1234567890abcdefghijklmnopqrstuvwxyz";

function GetRandomString($length) {

        global $template;

        settype($length, "integer");
        settype($rndstring, "string");
        settype($a, "integer");
        settype($b, "integer");
        
        for ($a = 0; $a <= $length; $a++) {
                $b = rand(0, strlen($template) - 1);
                $rndstring .= $template[$b];
        }
        
        return $rndstring;
        
}

echo GetRandomString(30);

?>

This is the output after running the script 5 times:

i7wwgx8p1x0mdhn6gnyqzcq3dpqsc0
5ntlvapx6o90notob4n7isdp0ohp19
ojnyuile9y459cjr1vf9kgdas4tscw
2fr5dqn62kzfjvywqczjaoyrqjeyfd
9dtnk7e18jjx1og4gr4noznldit0ba

The longer and more varied the text of $template, the more random your string will be, 
and the higher the value of GetRandomString(?), the more unique your string is.

Note also, if you pass a non-integer into the function, the settype($length) will force it to be 0, 
hence you won't get anything returned, so make sure you pass it a valid integer.