On 3/3/21 3:23 PM, Hans Ginzel wrote: > Please, is there a reason why extend() method does not return self? > >>>> a = [1,2].extend((3,4)) >>>> a >>>> type(a) > <class 'NoneType'> >>>> b = [1,2] >>>> b.extend((3,4)) >>>> b > [1, 2, 3, 4]
I think it just the general principle that mutating methods return None, while methods that create a new object return that object. Thus you use the return type if you expect a new object, and getting None alerts you to the fact that it mutated the original instead of just makeing a new object for the answer. -- Richard Damon _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/DJWSWQQCPTKDXE3EKVTUWESI44QMFZU7/ Code of Conduct: http://python.org/psf/codeofconduct/
