INADA Naoki <songofaca...@gmail.com> added the comment: > I think it's a reasonable expectation as a python user to be able to do > reversed(dict(a=1, b=20) since the order is know defined in the > specifications.
I agree about "reasonable expectation". But I'm interested in is it really useful in real world? > It seems inconsistent to have an order on dict, views and not have reversed > work on them. "Have an order" doesn't mean "reversible". For example, single linked list is ordered, but not reversible. While CPython implementation can provide efficient __reverse__, adding __reverse__ means **all** Python implementation is expected to provide it. For example, some Python implementation may be able to implement dict with hashmap + single linked list. If __reverse__ is added, it's not possible anymore. "Preserve insertion order" is very useful for many people. So it's guaranteed. Then how useful "reversible" in real world, for many people? ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue33462> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
