Question

I have two lists

    list1= [6, 1, 8, 1, 2]
   list2= ["Mail Opened", "Mail Not Opened", "Mail Opened", "Mail Not Opened", "Mail Not Opened"]

I was to trying results like

(14,"mailopened") (4,"mailnotopened")

First i tried to convert them Dict but it does not accept duplicate values.
is it Possible to add these lists according to the second list.

Answer 1

Use a defaultdict and simply add the values from list1.

from collections import defaultdict

list1 = [6, 1, 8, 1, 2]
list2 = ["Mail Opened", "Mail Not Opened", "Mail Opened", "Mail Not Opened", "Mail Not Opened"]

added = defaultdict(int)

for i, k in enumerate(list2):
    added[k] += list1[i]

This works because defaultdict supplies a default value if a key is accessed which doesn’t exist. In this case, it will supply a default of 0 because we specified that it is an int type.

Use of enumerate() stolen from @GaretJax. 🙂