Jerry Hill <malaclyp...@gmail.com> writes: > if foo == None: > do_stuff() > > The only time it would give you a different result from the "is" > version is if foo was bound to an object that returned True when > compared with None.
That's right. Python provides this singleton and then recommends you compare with ‘is’, precisely to protect against pathological cases like a “return True when compared for equality with None” data type. Using ‘if foo is None’ means you don't even have to spend time worrying about such cases. > And if that were the case, I'm still not convinced that you can tell > from looking at those two lines of code which one is buggy, except for > the fact that there has been 20 years of custom saying that comparing > to None with equality is wrong. Yes. And because of that widespread convention, it's much more correct to compare against None with ‘is’. -- \ “Always do right. This will gratify some people, and astonish | `\ the rest.” —Mark Twain | _o__) | Ben Finney -- https://mail.python.org/mailman/listinfo/python-list
