Last iteration?

Paul Hankin paul.hankin at gmail.com
Wed Oct 17 13:12:45 CEST 2007


On Oct 17, 8:16 am, Raymond Hettinger <pyt... at rcn.com> wrote:
> >     def lastdetecter(iterable):
> >         "fast iterator algebra"
> >         lookahead, t = tee(iterable)
> >         lookahead.next()
> >         t = iter(t)
> >         return chain(izip(repeat(False), imap(itemgetter(1),
> > izip(lookahead, t))), izip(repeat(True),t))
>
> More straight-forward version:
>
> def lastdetecter(iterable):
>     t, lookahead = tee(iterable)
>     lookahead.next()
>     return izip(chain(imap(itemgetter(0), izip(repeat(False),
> lookahead)), repeat(True)), t)

def lastdetector(iterable):
    t, u = tee(iterable)
    return izip(chain(imap(lambda x: False, islice(u, 1, None)),
        [True]), t)

--
Paul Hankin




More information about the Python-list mailing list