[StarWing]
> > > sometimes I want to iterate a part of a sequence. but don't want to
> > > copy it. i.e.
. . .
> I had checked it for serval times. maybe it's my inattention :-(. but
> what i could find the nearest thing is itertools.islice. but it can't
> process negative index -- that's supported by slice. so I need
> something, bind object with slice, and return a iter. I can find
> anything like it...:-(
If it really is a sequence (with len and getitem), you can write your
own indexing iterator:
def myslice(seq, start, stop, step):
'Allow forward or backwards iteration over a subslice'
for i in range(start, stop, step):
yield seq[i]
Raymond
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