Question

What is the most pythonic way of adding the values of two or more tuples to produce a total for each ‘column’?

Eg:

>>> a = (10, 20)
>>> b = (40, 50)
>>> c = (1, 3)
>>> ???
(51, 73)

I’ve so far considered the following:

def sumtuples(*tuples):
    return (sum(v1 for v1,_ in tuples), sum(v2 for _,v2 in tuples))

>>> print sumtuples(a, b, c)
(51, 73)

I’m sure this far from ideal – how can it be improved?

Answer 1

I guess you could use reduce, though it’s debatable whether that’s pythonic ..

In [13]: reduce(lambda s, t: (s[0]+t[0], s[1]+t[1]), [a, b, c], (0, 0))
Out[13]: (51, 73)

Here’s another way using map and zip:

In [14]: map(sum, zip(a, b, c))
Out[14]: [51, 73]

or, if you’re passing your collection of tuples in as a list:

In [15]: tups = [a, b, c]

In [15]: map(sum, zip(*tups))
Out[15]: [51, 73]

and, using a list comprehension instead of map:

In [16]: [sum(z) for z in zip(*tups)]
Out[16]: [51, 73]