On Mon, 7 Nov 2005 20:39:46 -0800, James Stroud <[EMAIL PROTECTED]> wrote:
>On Monday 07 November 2005 20:21, Robert Kern wrote: >> James Stroud wrote: >> > Hello All, >> > >> > How does one make an arbitrary class (e.g. class myclass(object)) behave >> > like a list in method calls with the "*something" operator? What I mean >> > is: >> > >> > myobj = myclass() >> > >> > doit(*myobj) >> > >> > I've looked at getitem, getslice, and iter. What is it if not one of >> > these? >> > >> > And, how about the "**something" operator? >> >> Avoiding magic at the expense of terseness, I would do something like >> the following: >> >> class myclass(object): >> def totuple(self): >> ... >> def todict(self): >> ... >> >> myargs = myclass() >> mykwds = myclass() >> >> doit(*myargs.totuple(), **mykwds.todict()) > >Actually, I retried __iter__ and it worked. I'm not sure how I screwed it up >before. So I'm happy to report a little "magic": > >py> def doit(*args): >... print args >... >py> class bob: >... def __init__(self, length): >... self.length = length >... def __iter__(self): >... return iter(xrange(self.length)) >... >py> b = bob(8) >py> list(b) >[0, 1, 2, 3, 4, 5, 6, 7] >py> doit(*b) >(0, 1, 2, 3, 4, 5, 6, 7) > I think you can also just define __getitem__ if that's handier. E.g., >>> class MyClass(object): ... def __init__(self, limit=1): self.limit=limit ... def __getitem__(self, i): ... if i < self.limit: return i**3 ... raise StopIteration ... >>> myobj = MyClass(5) >>> list(myobj) [0, 1, 8, 27, 64] >>> list(MyClass(10)) [0, 1, 8, 27, 64, 125, 216, 343, 512, 729] Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
