On 01.09.2021 10:27, Chris Angelico wrote: > On Wed, Sep 1, 2021 at 5:19 PM Steven D'Aprano <st...@pearwood.info> wrote: >> Outside of contrived counter-examples, we're not likely to come across >> anything trying to mimac None in the real world. But that's not really >> why we use `is`, or at least, it's not the only reason. There are a >> bunch of reasons, none of which on their own are definitive, but >> together settle the issue (in my opinion). >> >> 1. Avoid rare bugs caused by weird objects. >> 2. Slightly faster and more efficient. >> 3. Expresses the programmer's intent. >> 4. Common idiom, so the reader doesn't have to think about it. >> > > And in terms of education, these sorts of reasons are the things I > tend to wrap up behind the description "best practice". For instance, > why do we write file management using the 'with' statement? You could > argue that it's because other Python implementations may behave > differently, or future versions may behave differently, or there's the > risk that the file wouldn't be closed because of some other > reference... but the easiest explanation is "that's the standard > idiom", and then you can explain the reasons as the justifications for > it being standard.
I'm a bit puzzled by all this discussion around "is None". None is a singleton, so there can only be one such object in any Python process. Because there is only one, asking: if x is None: ... feels intuitive to me. if x == None: ... would also work, but misses the point about None being a singleton. BTW: In SQL you have to use "field IS NULL", "field = NULL" returns NULL, so you're not any smarter than before :-) -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Experts (#1, Sep 01 2021) >>> Python Projects, Coaching and Support ... https://www.egenix.com/ >>> Python Product Development ... https://consulting.egenix.com/ ________________________________________________________________________ ::: We implement business ideas - efficiently in both time and costs ::: eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 https://www.egenix.com/company/contact/ https://www.malemburg.com/ _______________________________________________ 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/46NOM3Y3RMTVEDIZIBHBFHOX2XVH764Q/ Code of Conduct: http://python.org/psf/codeofconduct/
