Alan Gauld schreef: > "Kent Johnson" <ken...@tds.net> wrote >> For what it's worth, Guido has explicitly said, >> "Tuples are for heterogeneous data, list are for homogeneous data. >> Tuples are *not* read-only lists." > > That surprises me, he has always seemed more pragmatist than purist. > However even Guido saying it doesn't alter the fact that in practice > it is not a part of the language, merely a usage pattern.
I think it's more than a usage pattern; I think it is also the idea behind the design decisions of list and tuple behavior. It's why lists have index() methods for example, and tuples don't. > Precisely. That was the point I tried to make earlier that in most > usage scenarios lists tend to be used homogenously and tuples > heterogenenously. But there is absolutely nothing in Python that > mandates it. A good example of a homogenous tuple is a pair of > values such as a point's x,y coordinates. In the point of view taken by Guido and the writer of the blogs mentioned before, a tuple of x, y coordinates is not homogeneous, it's heterogeneous. Both x and y do have the same type, but that's not the point. The point is that the meaning of the two elements is different. It makes, for example, no sense to sort such a tuple. -- The saddest aspect of life right now is that science gathers knowledge faster than society gathers wisdom. -- Isaac Asimov Roel Schroeven _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
