Question

How do you generate codes that should be 16 digits in length, unique, made up of 1-9, a-z and A-Z (case sensitive obviously so Abc1 is not the same as abc1) ex: Ahs78D7xkEshud45

I tried doing this but cannot seem to figure out the easiest way.

Thanks for your help!

Answer 1

If uniqueness isn’t of great importance, you can try this:

function randomString() {
    $length = 16;
    $chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    $str = "";    

    for ($i = 0; $i < $length; $i++) {
        $str .= $chars[mt_rand(0, strlen($chars) - 1)];
    }

    return $str;
}

For a more unique alternative use a hash function:

$str = substr(base64_encode(sha1(mt_rand())), 0, 16);