如何将列表中的字典组合成一个字典，并添加相同键的值？

Question

I am trying to convert a list that contains dictionaries to one dictionary where the values for common keys are added.

Use this list as an example:

list = [{'Apple': 3, 'Orange': 2}, {'Apple': 1, 'Grapes': 3, 'Orange': 1}, {'Apple': 2}]

I want a function that will take that list as an input and return the following as the output:

{'Apple': 6, 'Orange': 3, 'Grapes': 3}

Answer 1

from collections import Counter

fruit_dicts = [
    {'Apple': 3, 'Orange': 2},
    {'Apple': 1, 'Grapes': 3, 'Orange': 1},
    {'Apple': 2}
]

counter = Counter()
for fruit_dict in fruit_dicts:
    counter.update(fruit_dict)

print(counter)

Output:

Counter({'Apple': 6, 'Orange': 3, 'Grapes': 3})

EDIT Without using collections.Counter :

fruit_dicts = [
    {'Apple': 3, 'Orange': 2},
    {'Apple': 1, 'Grapes': 3, 'Orange': 1},
    {'Apple': 2}
]

counter = {}
for fruit_dict in fruit_dicts:
    for key, value in fruit_dict.items():
        counter.update({key: counter.get(key, 0) + value})

print(counter)