On Monday, February 2, 2015 at 10:57:27 AM UTC+5:30, Vito De Tullio wrote: > Steven D'Aprano wrote: > > > Checking the REPL first would have revealed that [].__dir__ raises > > AttributeError. In other words, lists don't have a __dir__ method. > > ? > > Python 3.4.2 (default, Nov 29 2014, 00:45:45) > [GCC 4.8.3] on linux > Type "help", "copyright", "credits" or "license" for more information. > >>> [].__dir__() > ['sort', '__contains__', '__init__', '__ge__', 'count', '__class__', > '__format__', '__mul__', 'index', '__rmul__', '__hash__', '__iter__', > 'clear', '__subclasshook__', '__getitem__', 'reverse', 'append', '__ne__', > 'pop', '__reduce__', '__add__', 'extend', '__gt__', '__sizeof__', > '__setattr__', '__imul__', '__dir__', '__le__', 'insert', '__repr__', > '__str__', '__getattribute__', '__len__', '__lt__', 'remove', '__new__', > '__reduce_ex__', 'copy', '__reversed__', '__delattr__', '__eq__', > '__setitem__', '__iadd__', '__doc__', '__delitem__'] > >>>
Sure But as I said (and probably Steven checked): $ python Python 2.7.8 (default, Oct 20 2014, 15:05:19) [GCC 4.9.1] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> [].__dir__ Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: 'list' object has no attribute '__dir__' --------------- My point was more methodological/sociological than technical: Are these dunder methods as 'internal' as say the register-allocation used by a C compiler? In which case the language implementer is entitled to tell the vanilla programmer: "Dunder methods (and their changingness) is none of your business" If however they are more on the public façade of the language then some better docs would be nice -- https://mail.python.org/mailman/listinfo/python-list
