[Solved] Adding the sorted elements in list

You can do that as follows:

from collections import defaultdict

a = [(1,22),(1,22),(2,29),(2,16),(3,56),(4,32),(4,12)]

b = defaultdict(lambda: 0)
for i,j in a:
    b[i] += j

>>> print b
{1:44, 2:45, 3:56, 4:44}