Steven D'Aprano wrote: > On Sat, 8 May 2010 02:07:55 am Rob Cliffe wrote: >> Sorry to grouse, but isn't this maybe being a bit too clever? >> Using your example, >> p1 = partial(operator.add) >> is creating a callable, p1, i.e. a sort of function. Yes I know >> technically it's not a function, but it behaves very much like one. >> >> Now, if I write >> >> def f1(x,y): return x+y >> def f2(x,y): return x+y >> >> I don't expect f1==f2 to be True, even though f1 and f2 behave in >> exactly the same way, >> and indeed it is not. > > I do expect f1==f2, and I'm (mildly) disappointed that they're not. > How about
def f1(x, y): return x+y def f2(x, y): return y+x As you know, there are limits to everything. It seems to me that while pure mathematics can (sometime) easily determine functional equivalence, once you get to code it's a lot harder because there are semantic constraints that don't apply in pure mathematics. > > [...] >> Similarly, if you wanted p1==p2, why not write >> >> p1 = partial(operator.add) >> p2 = p1 > > I thought the OP gave a use-case. He's generating "jobs" (partial > applied to a callable and arguments), and wanted to avoid duplicated > jobs. > > I think it is reasonable to expect that partial(operator.add, 2) > compares equal to partial(operator.add, 2). I don't think he's > suggesting it should compare equal to partial(lambda x,y: x+y, 2). > Which absence, presumably, also mildly disappoints you? regards Steve > +0.5 on comparing equal. > +1 on a nicer repr for partial objects. > > > -- Steve Holden +1 571 484 6266 +1 800 494 3119 See PyCon Talks from Atlanta 2010 http://pycon.blip.tv/ Holden Web LLC http://www.holdenweb.com/ UPCOMING EVENTS: http://holdenweb.eventbrite.com/ _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
