On Sun, Mar 1, 2009 at 8:54 AM, Gabriel Genellina <gagsl-...@yahoo.com.ar> wrote: > En Sun, 01 Mar 2009 13:20:28 -0200, John O'Hagan <resea...@johnohagan.com> > escribió: > >> Inspired by some recent threads here about using classes to extend the >> behaviour of iterators, I'm trying to replace some some top-level >> functions >> aimed at doing such things with a class. >> >> So far it's got a test for emptiness, a non-consuming peek-ahead method, >> and >> an extended next() which can return slices as well as the normal mode, but >> one thing I'm having a little trouble with is getting generator >> expressions >> to restart when exhausted. This code works for generator functions: > > [...] > >> I'd like to do the same for generator expressions, something like: >> >> genexp = (i for i in range(3)) >> >> regenexp = Regen(genexp, restart=True) >> >> such that regenexp would behave like reg, i.e. restart when exhausted (and >> would only raise StopIteration if it's actually empty). However because >> generator expressions aren't callable, the above approach won't work. > > I'm afraid you can't do that. There is no way of "cloning" a generator:
Really? What about itertools.tee()? Sounds like it'd do the job, albeit with some caveats. http://docs.python.org/library/itertools.html#itertools.tee Cheers, Chris -- Follow the path of the Iguana... http://rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
