What does the caret operator (^) in Python do?

Question

I ran across the caret operator in python today and trying it out, I got the following output:

>>> 8^3
11
>>> 8^4
12
>>> 8^1
9
>         


        

Answer 1

Generally speaking, the symbol ^ is an infix version of the __xor__ or __rxor__ methods. Whatever data types are placed to the right and left of the symbol must implement this function in a compatible way. For integers, it is the common XOR operation, but for example there is not a built-in definition of the function for type float with type int:

In [12]: 3 ^ 4
Out[12]: 7

In [13]: 3.3 ^ 4
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
 in ()
----> 1 3.3 ^ 4

TypeError: unsupported operand type(s) for ^: 'float' and 'int'

One neat thing about Python is that you can override this behavior in a class of your own. For example, in some languages the ^ symbol means exponentiation. You could do that this way, just as one example:

class Foo(float):
    def __xor__(self, other):
        return self ** other

Then something like this will work, and now, for instances of Foo only, the ^ symbol will mean exponentiation.

In [16]: x = Foo(3)

In [17]: x
Out[17]: 3.0

In [18]: x ^ 4
Out[18]: 81.0