Question

Why is () is () true, yet (0,) is (0,) is false?

I thought they would be the same object. However, I’m apparently missing something.

Answer 1

is tests to see if both sides of the statement share the same memory address. It’s basically a shorthand for id(a) == id(b)

>>> print id(()), id(())
30085168 30085168
>>> print id((0,)), id((0,))
38560624 38676432
>>>

As () happens fairly frequently, it is actually treated as a singleton by the Python Interpreter (just like integers from 0 to 255, empty strings, empty lists, etc.). When comparing (0, ) to (0, ) to the interpreter they are actually different variables in memory. If they were mutable, you could modify the first, and the second wouldn’t change, hence they are not the same (a is not b).