Guido van Rossum wrote: > BTW, what should > > [a, b, *rest] = (1, 2, 3, 4, 5) > > do? Should it set rest to (3, 4, 5) or to [3, 4, 5]?
Whatever type is chosen, it should be the same type, always. The rhs could be any iterable, not just a tuple or a list. Making a special case of preserving one or two types doesn't seem worth it to me. > Suppose the latter. Then should we allow > > [*rest] = x > > as alternative syntax for > > rest = list(x) That would be a consequence of that choice, yes, but so what? There are already infinitely many ways of writing any expression. > ? And then perhaps > > *rest = x > > should mean > > rest = tuple(x) > > Or should that be disallowed Why bother? What harm would result from the ability to write that? > There certainly is a need for doing the same from the end: > > *rest, a, b = (1, 2, 3, 4, 5) I wouldn't mind at all if *rest were only allowed at the end. There's a pragmatic reason for that if nothing else: the rhs can be any iterable, and there's no easy way of getting "all but the last n" items from a general iterable. > Where does it stop? For me, it stops with *rest only allowed at the end, and always yielding a predictable type (which could be either tuple or list, I don't care). > BTW, and quite unrelated, I've always felt uncomfortable that you have to > write > > f(a, b, foo=1, bar=2, *args, **kwds) > > I've always wanted to write that as > > f(a, b, *args, foo=1, bar=2, **kwds) Yes, I'd like that too, with the additional meaning that foo and bar can only be specified by keyword, not by position. Greg _______________________________________________ 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
