Python tuple operations

Question

Is there anyway to get tuples operation in python to work like this:

>>>a = (1,2,3)
>>>b = (3,2,1)
>>>a + b
(4,4,4)

instead of:

>>>a = (1,2,3)
>>>b = (3,2,1)
>>>a + b
(1,2,3,3,2,1)

I know it works like that because the __add__ and __mul__ methods are defined to work like that. So the only way would be to redefine them?

Answer 1

import operator
tuple(map(operator.add, a, b))

Answer 2

Yes. But you can't redefine built-in types. You have to subclass them:

class MyTuple(tuple):
    def __add__(self, other):
         if len(self) != len(other):
             raise ValueError("tuple lengths don't match")
         return MyTuple(x + y for (x, y) in zip(self, other))

Answer 3

Sort of combined the first two answers, with a tweak to ironfroggy's code so that it returns a tuple:

import operator

class stuple(tuple):
    def __add__(self, other):
        return self.__class__(map(operator.add, self, other))
        # obviously leaving out checking lengths

>>> a = stuple([1,2,3])
>>> b = stuple([3,2,1])
>>> a + b
(4, 4, 4)

Note: using self.__class__ instead of stuple to ease subclassing.

Answer 4

What others have said so far is correct, but if you're more generally interested in vectorizing your code, you might want to check out NumPy arrays.

Answer 5

map(sum,zip(a,b))

Answer 6

simple solution without class definition that returns tuple

import operator
tuple(map(operator.add,a,b))