On Sat, Mar 12, 2016 at 8:53 AM, Charles T. Smith <cts.private.ya...@gmail.com> wrote: > On Fri, 11 Mar 2016 21:44:27 +0000, Charles T. Smith wrote: > >> From the performance point of view, which is better: - hasattr() >> - x in y >> >> TIA >> cts > > > I just realized that "in" won't look back through the class hierarchy... > that clearly makes them not interchangable, but given we're only > interested in the current dict...
They're still completely different - hasattr looks at attributes, but the 'in' operator looks at the object's members (in the case of a dictionary, the keys). There is a broad similarity between "hasattr(obj, attrname)" and "attrname in obj.__dict__", but if you're doing the latter, you have other problems than performance; attributes should be looked up as attributes, not as dictionary members. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
