元组中的和值（dict中的值）

Question

I have a dictionary data that looks like that with sample values:

defaultdict(<type 'list'>, 
{(None, 2014): [(5, 1), (10, 2)], 
(u'Middle', 2014): [(6, 2), (11, 3)],
(u'SouthWest', 2015): [(7,3), (12, 4)]})

I get this from collections.defaultdict(list) because my keys have to be lists.

My goal is to get a new dictionary that will contain the sum values for every tuple with respect to their position in the tuple.

By running

out = {k:(sum(tup[0] for tup in v),sum(tup[1] for tup in v)) for k,v in data.items()}

I get

{(None, 2014): (15, 3),  (u'Middle', 2014): (17, 5), (u'SouthWest', 2015): (19, 7)}

However, I don't know in advance how many items will be in every tuple, so using the sum(tup[0] for tup in v) with hard-coded indices is not an option. I know, however, how many integers will be in the tuple. This value is an integer and I get this along with the data dict. All tuples are always of the same length (in this example, of length 2).

How do I tell Python that I want the out dict to contain tuple of the size that matches the length I have to use?

Answer 1

I think you want the built-in zip function :

In [26]: {k: tuple(sum(x) for x in zip(*v)) for k, v in data.items()}
Out[26]: 
{('SouthWest', 2015): (19, 7),
 (None, 2014): (15, 3),
 ('Middle', 2014): (17, 5)}