Question

I want to generate a random 5 digit number for a file name, with exception.
If PHP will generate for example the number 65, I want to be set 00065 (only 5 digit).
I have a array who contains a exception for the generator:

$uploaded_files= array(00178, 49856, 32183, 02004, 01585);
In the array are the file names who already exists, and the number generator is very important to omit them, to avoid possible errors.
Thank you.

Answer 1

Consider not to re-invent the wheel, especially when the wheel is available in your language in one way or another. That being said:

/**
 * Get random number outside an exception list
 *
 * @param array $exception Exception list
 */
function getRandom($exception=array('00001', '00002', '00003', '00004', '00005')) {
    $rand=str_pad(mt_rand(0,10),5,0,STR_PAD_LEFT);
    if(in_array($rand,$exception))return getRandom($exception);
    return $rand;
}

var_dump(
    getRandom(),
    getRandom(),
    getRandom(),
    getRandom(),
    getRandom(),
    getRandom()
);

Do take note, this kind of implementation can really expensive on collisions really fast, especially if the exception list grows.