looking for a neat solution to a nested loop problem
88888 Dihedral
dihedral88888 at googlemail.com
Thu Aug 9 14:39:56 EDT 2012
Nobody於 2012年8月7日星期二UTC+8下午11時32分55秒寫道:
> On Mon, 06 Aug 2012 21:02:33 -0700, Larry Hudson wrote:
>
>
>
> >> for i in range(N,N+100):
>
> >> for j in range(M,M+100):
>
> >> do_something(i % 100 ,j % 100)
>
> >>
>
> >> Emile
>
> >
>
> > How about...
>
> >
>
> > for i in range(100):
>
> > for j in range(100):
>
> > do_something((i + N) % 100, (j + M) % 100)
>
>
>
> Both of these approaches move the modifications to the sequence into the
>
> body of the loop. It may be preferable to iterate over the desired
>
> sequence directly. E.g.
>
>
>
> for i in ((N + ii) % 100 for ii in xrange(100)):
>
> for j in ((M + jj) % 100 for jj in xrange(100)):
>
> do_something(i, j)
Nobody於 2012年8月7日星期二UTC+8下午11時32分55秒寫道:
> On Mon, 06 Aug 2012 21:02:33 -0700, Larry Hudson wrote:
>
>
>
> >> for i in range(N,N+100):
>
> >> for j in range(M,M+100):
>
> >> do_something(i % 100 ,j % 100)
>
> >>
>
> >> Emile
>
> >
>
> > How about...
>
> >
>
> > for i in range(100):
>
> > for j in range(100):
>
> > do_something((i + N) % 100, (j + M) % 100)
>
>
>
> Both of these approaches move the modifications to the sequence into the
>
> body of the loop. It may be preferable to iterate over the desired
>
> sequence directly. E.g.
>
>
>
> for i in ((N + ii) % 100 for ii in xrange(100)):
>
> for j in ((M + jj) % 100 for jj in xrange(100))
list(range(N,100))+list(range(1,N)) //good for i
I contribute my python code here to avoid any divison.
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