Christoph Zwerschke <[EMAIL PROTECTED]> wrote: > Alex Martelli schrieb: > > Christoph Zwerschke <[EMAIL PROTECTED]> wrote: > > ... > >> given length. You could get a 6/49 lotto tip with something like: > >> > >> choice(set(range(49)).powerset(6)) > > > And that would be better than the current random.sample(range(49),6) in > > WHAT ways, exactly...? > > You're right, random.sample(range(49),6) does the same and much faster. > I just didn't think of it (it is new since Python 2.3).
Yep, it's one of 2.3's many little gems. Still, builtin set is new in 2.4, so it's hardly a "more classic" approach;-). > What if you need 12 different tips for your lotto ticket? You probably want random ones, then... > s = set(range(49)).powerset(6) > for x in range(10): > print s.pop() This is very systematic, not random;-). Still, using random.sample on s would indeed produce 12 random different tips!-) > But the real disadvantage of this idea is the memory consumed and the > time to set up that memory: set(range(49)).powerset(6) has a cardinality > of about 13 million entries! You PC would start to swap just for getting > a lotto tip... Well then, you need a new PC, 64-bit and with as many GB of RAM as required, no?-) Until you get such a PC, something like: tips = set() while len(tips) < 10: tip = frozenzet(random.sample(range(49), 6)) tips.add(tip) will have to suffice, I guess;-). Alex -- http://mail.python.org/mailman/listinfo/python-list
