Python list set dictionary sums the values with the same key (addition)

created at 07-28-2021 views: 4

Python list set dictionary sums the values with the same key (addition)

The first use: reduce() + operator

import collections, functools, operator

# Initialising list of dictionary
ini_dict = [{'a':5, 'b':10, 'c':90},
            {'a':45, 'b':78}, 
            {'a':90, 'c':10}]


# printing initial dictionary
print ("initial dictionary", str(ini_dict))

# sum the values with same keys
result = dict(functools.reduce(operator.add,
         map(collections.Counter, ini_dict)))

print("resultant dictionary : ", str(result))

The second type: counter

# Python code to demonstrate
# return the sum of values of dictionary
# with same keys in list of dictionary

import collections

# Initialising list of dictionary
ini_dict = [{'a':5, 'b':10, 'c':90}, 
            {'a':45, 'b':78},
            {'a':90, 'c':10}]

# printing initial dictionary
print ("initial dictionary", str(ini_dict))

# sum the values with same keys
counter = collections.Counter()
for d in ini_dict: 
    counter.update(d)

result = dict(counter)


print("resultant dictionary : ", str(counter))

initial dictionary [{‘c’: 90, ‘a’: 5, ‘b’: 10}, {‘a’: 45, ‘b’: 78}, {‘a’: 90, ‘c’: 10}]
resultant dictionary : Counter({‘a’: 140, ‘c’: 100, ‘b’: 88})

The third common method

# Python code to demonstrate
# return the sum of values of dictionary
# with same keys in list of dictionary

from operator import itemgetter

# Initialising list of dictionary
ini_dict = [{'a':5, 'b':10, 'c':90},
            {'a':45, 'b':78}, 
            {'a':90, 'c':10}]

# printing initial dictionary
print ("initial dictionary", str(ini_dict))

# sum the values with same keys
result = {}
for d in ini_dict:
    for k in d.keys():
        result[k] = result.get(k, 0) + d[k]


print("resultant dictionary : ", str(result))

initial dictionary [{‘b’: 10, ‘c’: 90, ‘a’: 5}, {‘b’: 78, ‘a’: 45}, {‘c’: 10, ‘a’: 90}]
resultant dictionary : {‘b’: 88, ‘c’: 100, ‘a’: 140}
created at:07-28-2021
edited at: 07-28-2021: