Python | Sum list of dictionaries with same key
You have given a list of dictionaries, the task is to return a single dictionary with sum values with the same key.
Let’s discuss different methods to do the task.
Method #1: Using reduce() + operator
# Python code to demonstrate# return the sum of values of dictionary# with same keys in list of dictionary import collections, functools, operator # Initialising list of dictionaryini_dict = [{'a':5, 'b':10, 'c':90}, {'a':45, 'b':78}, {'a':90, 'c':10}] # printing initial dictionaryprint ("initial dictionary", str(ini_dict)) # sum the values with same keysresult = dict(functools.reduce(operator.add, map(collections.Counter, ini_dict))) print("resultant dictionary : ", str(result)) |
Output:
initial dictionary [{‘b’: 10, ‘a’: 5, ‘c’: 90}, {‘b’: 78, ‘a’: 45}, {‘a’: 90, ‘c’: 10}]
resultant dictionary : {‘b’: 88, ‘a’: 140, ‘c’: 100}
Method #2: Using counter
# Python code to demonstrate# return the sum of values of dictionary# with same keys in list of dictionary import collections # Initialising list of dictionaryini_dict = [{'a':5, 'b':10, 'c':90}, {'a':45, 'b':78}, {'a':90, 'c':10}] # printing initial dictionaryprint ("initial dictionary", str(ini_dict)) # sum the values with same keyscounter = collections.Counter()for d in ini_dict: counter.update(d) result = dict(counter) print("resultant dictionary : ", str(counter)) |
Output:
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})
Method #3: Naive 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 dictionaryini_dict = [{'a':5, 'b':10, 'c':90}, {'a':45, 'b':78}, {'a':90, 'c':10}] # printing initial dictionaryprint ("initial dictionary", str(ini_dict)) # sum the values with same keysresult = {}for d in ini_dict: for k in d.keys(): result[k] = result.get(k, 0) + d[k] print("resultant dictionary : ", str(result)) |
Output:
initial dictionary [{‘b’: 10, ‘c’: 90, ‘a’: 5}, {‘b’: 78, ‘a’: 45}, {‘c’: 10, ‘a’: 90}]
resultant dictionary : {‘b’: 88, ‘c’: 100, ‘a’: 140}
