On Mar 14, 4:57 pm, Jarek Zgoda <[EMAIL PROTECTED]> wrote: > Lie napisa³(a): > > > > >> foo = [1,2,3,4] > >> x = foo.append(5) > >> print x > > >> What will be the output (choose one): > > >> 1) [1,2,3,4] > >> 2) [1,2,3,4,5] > >> 3) That famous picture of Albert Einstein sticking out his tongue > >> 4) Nothing - no output > >> 5) None of the above > > >> I undertake to summarise answers posted to complete this "survey". > > > I think I'll choose 3. Well, no, I suppose the correct behavior > > _should_ be undefined (i.e. what it returns is an implementation > > details that should not be relied on). The fact that it returns None > > is just a "coincidence" that happens to happen every time you tested > > it (you can't prove by ignorance) > > I think in Python there's no notion of "void" return type. Deliberate > choice to return None for functions that modify objects in place seems > to be OK as long as it is used consistently and documented. Which is the > case.
No, there is no need for "void" return type, what I meant is that everything that's not said in the documentation should be assumed to be an implementation detail, a method or a function that doesn't say anything about its return type should be assumed to return an implementation detail (which basically means: Don't rely on this). The fact that list.append returns none is just a coincidence, you might encounter another list.append that returns different thing some time in the future, or the far future, or perhaps at the end of the galaxy's life. -- http://mail.python.org/mailman/listinfo/python-list
