Python list group and sum with more fields

Question

I have a list with two integer fields which I would like to sum (string,integer, integer)

myList= [[[\"26-07-2017\",2,0], [\"26-07-2017\",3,0], [\"27-07-2017\",         


        

Answer 1

I would use a dictionary to keep track of like first entries, as so:

my_dict = {}
for entry in myList:
    if entry[0] not in my_dict:
        #This makes my_dict hold dates as keys and a list of 2 integers as values
        my_dict[entry[0]] = [entry[1:]]
    else:
        #In the case that the date is already in my_dict, add the new integers
        my_dict[entry[0]][0] += entry[1]
        my_dict[entry[0]][1] += entry[2]
#Now my_dict holds dates as keys with all the sums following
#If I really need it to be in the list format you asked for:
sumList = []
for value in my_dict:
    sumList.append(value, my_dict[value][0], my_dict[value][1])