Summing/combining tuples

[Dan Sommers]

On Sat, 21 May 2016 03:19:49 +0000, Dan Sommers wrote:

>> Is there something shorter and sweeter for the summation?
> 
>     from itertools import groupby
>     from operator import itemgetter
> 
>     result = [(k,
>                sum(map(itemgetter(2), v)),
>                sum(map(itemgetter(3), v)))
>               for (k, v) in [(k, list(v))
>                              for (k, v)
>                              in groupby(aList, itemgetter(1))]])

Or even:

    from itertools import groupby
    from operator import itemgetter
    from functools import reduce

    result = [(k, *reduce(lambda acc, item: (acc[0] + item[2],
                                             acc[1] + item[3]),
                          v,
                          (0, 0)))
              for (k, v) in groupby(aList, itemgetter(1))]