Antoine Pitrou added the comment: > PS: Try being a bit more polite.
You could definitely do some research before posting erroneous statements (this one isn't difficult to check, as Alex showed). Especially when the other posters (Alex and Raymond) are a lot more competent than you on the topic at hand. If you actually try to *reason* about it, there is no other way for: x[k] += <some_expr> to work in the general case than to execute x.__setitem__(k, x.__getitem__(k) + <some_expr>) So, yes, the lookup is done twice, because it currently can't work otherwise. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue21101> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com