Random string generation php

Question

Below is the code for random string generation, it is working but there is some problem here which I at the moment cant figure out what happens here is that it always returns me value of length 1 ,I am expecting a random string of length 10. Also I am passing 10 as length. Kindly guide me what am I doing wrong here.

<?php 
function random_string($length) {
    $len = $length;
    $base = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz123456789";
    $max = strlen($base) - 1;
    $activatecode = '';
    mt_srand((double) microtime() * 1000000);

    while (strlen($activatecode) < $len + 1) {
        $activatecode.=$base{mt_rand(0, $max)};

        return $activatecode;
    }
}

?>

matthiasmullie · Accepted Answer · 2011-11-21 15:40:28Z

6

you return from within the while, causing the while-loop to only be run once and returning the result at that point (which is only 1 character)

Move your return-line 1 down (out of the while-loop) and it should work.

answered Nov 21, 2011 at 15:40

matthiasmullie

2,08316 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

noobie-php Over a year ago

/facepalm that worked lol sopme time copy pastes are worst then you think THx for answering

hakre · Accepted Answer · 2011-11-21 16:01:14Z

2

Your return statement is inside of the while loop making it to exit the function immediately, move it to the end of the function.

Some additional remarks:

No need for mt_srand((double) microtime() * 1000000); nowadays.
Don't use strlen, you don't need it.
{} substring syntax is outdated.

Example:

<?php 
function random_string($length)
{
    $length = (int) $length;
    if ($length < 1) return '';

    $base = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz123456789";
    $max = strlen($base) - 1;

    $string = '';    
    while ($len--)
    {
        $string .= $base[mt_rand(0, $max)];
    }
    return $string;
}    
?>

I suggest you add a maximum length as well, just in case.

answered Nov 21, 2011 at 16:01

hakre

200k55 gold badges454 silver badges866 bronze badges

Comments

Naftali · Accepted Answer · 2011-11-21 15:40:58Z

1

Seem to work fie for me.

Fix you code up a bit:

function random_string($length) {
 $len = $length;
 $base = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz123456789";
 $max = strlen($base) - 1;
 $activatecode = '';
 mt_srand((double) microtime() * 1000000);

 while (strlen($activatecode) < $len + 1) {
    $activatecode.=$base[mt_rand(0, $max)];
 }

    return $activatecode;
}

Demo: http://codepad.org/gq0lqmB3

answered Nov 21, 2011 at 15:40

Naftali

147k41 gold badges247 silver badges304 bronze badges

Comments

Peter · Accepted Answer · 2011-11-21 15:41:42Z

1

Your return statement is inside of the while loop.

Move it outside to be after the end of the while loop.

answered Nov 21, 2011 at 15:41

Peter

6,3821 gold badge34 silver badges30 bronze badges

Comments

Saud Iqbal · Accepted Answer · 2013-04-24 05:39:50Z

1

Just curious, whats the point of multiplying microtime() * 1000000?

each time microtime() is called it will produce a different seed!

answered Apr 24, 2013 at 5:39

Saud Iqbal

3831 gold badge4 silver badges18 bronze badges

Collectives™ on Stack Overflow

Random string generation php

5 Answers 5

1 Comment

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

1 Comment

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related