On Fri, 20 Nov 2015 15:38:36 +1100, Steven D'Aprano <st...@pearwood.info> wrote:
>On Fri, 20 Nov 2015 03:05 pm, Seymore4Head wrote: > >> Why does a work and b doesn't? What I was trying to accomplish with b >> is to get a random list (of random length) that could have digits >> repeat. >> >> I got idea for both methods from the Internet. I do see that one uses >> brackets and the other doesn't, but I don't know the difference. >> >> import random >> for i in range (5): >> a = random.sample(range(10), random.randrange(3,6)) >> print a > >Break it up, step by step. > >range(10) produces a list from 0 to 9. random.randrange(3, 6) produces a >single integer from 3 to 5 (6 is excluded). Let's say by chance it produces >the number 4. > >Then random.sample takes the list, and the integer 4, and selects 4 values >at random from the list. Say, something like this: > >[8, 6, 7, 0] > >Note that random.sample does NOT repeat selections. The numbers will always >be unique. > > > >> for i in range (5): >> b = [random.randrange (10), random.randrange(4,8)] >> print b > >As above, run through this step by step. > >random.randrange(10) produces a single number at random between 0 and 9 (10 >is excluded). Let's say it picks 8. > >random.randrange(4,8) produces a single number at random between 4 and 7 (8 >is excluded). Let's say it picks 5. > >Then b is set to the list [8, 5]. > >This list will always have two items. > > > >If you want a random number of digits that might repeat: > >[random.randrange(10) for i in range(random.randrange(1, 21))] > >will produce a random number between 1 and 20 (21 is excluded). Let's say it >picks 6. > >then range(6) produces the list [0, 1, 2, 3, 4, 5], and "for i in range..." >will iterate over those values. Although i is not used, this ends up >looping 6 times. > >For each loop, random.randrange(10) produces a random digit between 0 and 9 >(10 is excluded). So we end up with something like: > >[6, 4, 2, 2, 6, 9] > >for example. That works. Thanks -- https://mail.python.org/mailman/listinfo/python-list
