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Groups > comp.lang.python > #20002

Re: Cycle around a sequence

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Mark Lawrence schrieb:
> I'm looking at a way of cycling around a sequence i.e. starting at some
> given location in the middle of a sequence and running to the end before
> coming back to the beginning and running to the start place.  About the
> best I could come up with is the following, any better ideas for some
> definition of better?

# quick&dirty

seq=range(10)
for x in seq[4:]+seq[:4]:
     print x

# or

def oneround(seq, start=0):
     i=start
     l=len(seq)
     while True:
         yield seq[i]
         i = (i+1) % l
         if i==start: break

for x in oneround(range(50), 4):
     print x

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Cycle around a sequence Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-02-08 01:10 +0000
  Re: Cycle around a sequence Christoph Hansen <ch@radamanthys.de> - 2012-02-08 03:01 +0100
  Re: Cycle around a sequence Neil Cerutti <neilc@norwich.edu> - 2012-02-08 14:25 +0000
    Re: Cycle around a sequence Terry Reedy <tjreedy@udel.edu> - 2012-02-08 15:15 -0500
    Re: Cycle around a sequence Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-02-08 22:47 +0000
    Re: Cycle around a sequence Serhiy Storchaka <storchaka@gmail.com> - 2012-02-09 12:10 +0200
  Re: Cycle around a sequence Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-09 03:55 +0000
    Re: Cycle around a sequence Chris Angelico <rosuav@gmail.com> - 2012-02-09 15:16 +1100
    Re: Cycle around a sequence Peter Otten <__peter__@web.de> - 2012-02-09 09:33 +0100
    Re: Cycle around a sequence Chris Angelico <rosuav@gmail.com> - 2012-02-09 21:34 +1100

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