On Thu, 21 Apr 2022 at 06:20, Avi Gross via Python-list <python-list@python.org> wrote: > > This does raise an issue, Chris, if you use the method of making a tuple > companion for a list at a specific time just for use as a dictionary key, > then later change the list, you can end up with various situations. >
Yes. And those situations are *exactly* why you can't use a list as a key. > Obviously the changed list can not only not access the stored item, but if > converted again to a tuple, may address a different item. I can see many > scenarios with abandoned dictionary items that are never deleted and can only > be reached by examining all items in the dictionary. > So mutability is only one concern. If you actually mutate your data, ... And if you don't mutate your data, use a tuple. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
