Sum numbers by letter in list of tuples

Question

I have a list of tuples:

[ (\'A\',100), (\'B\',50), (\'A\',50), (\'B\',20), (\'C\',10) ]

I am trying to sum up all numbers that have the s

Answer 1

How about this: (assuming a is the name of the tuple you have provided)

letters_to_numbers = {}
for i in a:
    if i[0] in letters_to_numbers:
        letters_to_numbers[i[0]] += i[1]
    else:
        letters_to_numbers[i[0]] = i[1]
b = letters_to_numbers.items()

The elements of the resulting tuple b will be in no particular order.