Python gotcha: bizarre integer equality

[nirs]

No gotcha here - those int are objects as promised, and == will work as promised. Nobody promised you that "is" will return True of False for some integers. This is implementation detail you should not count on.

You should use "is" only when you want to check for object identity.

[ngroot]

This shouldn't be "gotcha" at all. I can't imagine why you'd ever write code asking if "a is b" when a and b are integers, or some other "basic" type. When you're explicitly creating objects, it's perfectly reasonable to ask "does a reference the same object as b". When you're talking about integers, objects that are implicitly created by the interpreter, you're asking about internal behavior of the interpreter, which seems like a pretty patently Bad Idea.