Raymond Hettinger <rhettin...@users.sourceforge.net> added the comment:
Other thoughts: Currently the __getitem__ method is inherited from tuple. That means that for normal tuple operations, a named tuple has no performance penalty (no pure python code is called). If __getitem__ were overridden, there would be a substantial additional cost. Currently, nt[x] raises IndexError if x is not an index a valid range, but mappings expect a KeyError for missing items. Switching to a LookupError would break existing code that catches IndexError. The collections.Mapping ABC suggests that anything trying to be a mapping should also provide items(), keys(), values(), and get(). These don't make much sense for named tuples. The semantics of __iter__ differ for Mappings and Sequences. The former returns keys and the latter returns values. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue5205> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
