On Tue, Jul 05, 2016 at 03:05:45PM -0400, Alex Hall wrote: > >>> a = 5 > >>> isinstance(a, int) > True > >>> a is int > False > > What happened there? Don't these do the same thing? I thought I could use > them interchangeably?
You're probably thinking of "is a", as in, "5 is an int", "'Hello World' is a str", "[1, 2, 3] is a list", etc. Python doesn't have an operator for testing "is a" relationships, it uses isinstance(obj, type). There's also issubclass(), for testing whether one class is a subclass of another. "x is y" checks whether the two operands x and y are the same object. That's *not* the same as checking whether they are equal. You should hardly ever use "is" in Python, with the exception of testing for None: "if obj is None: ..." sort of thing. -- Steve _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
