Op 02-09-15 om 14:45 schreef Chris Angelico: > On Wed, Sep 2, 2015 at 10:26 PM, Steven D'Aprano <st...@pearwood.info> wrote: >>> I think I understand how it gets these results >>> but I'm not really happy with them. I think python >>> should give the second result in both cases. >> Apart from breaking backwards compatibility, how would you implement such a >> thing? A simple left-to-right assignment rule is easy to implement and easy >> to understand even when the targets depend on each other. > I don't think this is really a question of implementation - it's a > design question of "should". > > The current behaviour is reasonably sane.
Yes it is reasonable sane, I just think the alternative would be saner. > But if you're confused by > it, there's a simple solution: Don't reference the same "thing" more > than once on the LHS. That is rather extreme. It would mean we avoid the following: a[i], b[i] = b[i], a[i] # references i twice on the LHS. a[i], a[j] = a[j], a[i] # references a twice on the LHS. I think a better rule would be: Don't reference and bind the same "thing" on the LHS. -- Antoon Pardon -- https://mail.python.org/mailman/listinfo/python-list
