My understanding is that python created functions like type() and len() as a general purpose way to get information and ALSO set up a protocol that classes can follow by creating dunder methods. I think the most pythonic things is to avoid directly calling the dunder methods with a few exceptions that mainly happen when you are building or extending classes. I mean some dunder methods are then called directly to avoid getting into infinite loops that would be triggered.
And note in many cases, the protocol is more complex. Is a length built-in? If not, can the object be iterated and you count the results? Calling the function len() may get you more info as it can leverage such things. And it means you can sometimes leave out some methods and your code still works. Be warned that type() is a very special function in python and when called with more arguments, does many relatively beautiful but unrelated things. It has a special role in the class or type hierarchy. But used with a single argument, it harmlessly return a result you want. -----Original Message----- From: Python-list <python-list-bounces+avi.e.gross=gmail....@python.org> On Behalf Of Thomas Passin Sent: Thursday, March 2, 2023 6:43 PM To: python-list@python.org Subject: Re: Which more Pythonic - self.__class__ or type(self)? On 3/2/2023 5:53 PM, Greg Ewing via Python-list wrote: > On 3/03/23 9:54 am, Ian Pilcher wrote: >> I haven't found >> anything that talks about which form is considered to be more Pythonic >> in those situations where there's no functional difference. > > In such cases I'd probably go for type(x), because it looks less > ugly. > > x.__class__ *might* be slightly more efficient, as it avoids a > global lookup and a function call. But as always, measurement > would be required to be sure. Except that we don't know if "efficiency" - whatever that might mean here - matters at all. -- https://mail.python.org/mailman/listinfo/python-list -- https://mail.python.org/mailman/listinfo/python-list
