On morning's light, that won't do what you think. random.sample() gives you a unique sampling. No character will be repeated. try this instead: alphanum =

On morning's light, that won't do what you think. random.sample() gives you a unique sampling. No character will be repeated. try this instead: alphanum = string.letters+string.digits ''.join([alphanum[random.randint(0,61)] for i in xrange(12)])