Answers for "how to add duplicate keys to dict"

switching keys and values in a dictionary in python [duplicate]

my_dict = {2:3, 5:6, 8:9}

new_dict = {}
for k, v in my_dict.items():
    new_dict[v] = k

how to merge two dictionaries with same keys in python

from collections import defaultdict

d1 = {1: 2, 3: 4}
d2 = {1: 6, 3: 7}

dd = defaultdict(list)

for d in (d1, d2): # you can list as many input dicts as you want here
    for key, value in d.items():
        dd[key].append(value)

print(dd)