I have a list of dictionary:

data = [
    {"2010" : {'A' : 2,'B' : 3,'C' : 5,}},    
    {"2011" : {'A' : 1,'B' : 2,}},
    {"2010" : {'A' : 1,'B' : 2,}}
]

I'd like sum the values where the key is same. So the result I expected should be like this:

res =
    {"2010" : {'A' : 3, 'B' : 5, 'C' : 5},
     "2011" : {'A' : 1, 'B' : 2}}

How can I do this easily?

CodePudding user response：

So you have a list of dictionaries as input and you want to create an output dictionary which contains the sums:

from collections import defaultdict

data = [{'2010': {'A': 2, 'B': 3, 'C': 5}}, {'2011': {'A': 1, 'B': 2}}, {'2010': {'A': 1, 'B': 2}}]

def sum_values(data):
    out = {}
    for i in data:
        for k in i.keys():
            if k not in out:
                out[k] = defaultdict(int)
            for k1,v1 in i[k].items():
                out[k][k1]  = v1
    return out

sum_values(data)
{'2010': defaultdict(<class 'int'>, {'A': 3, 'B': 5, 'C': 5}), '2011': defaultdict(<class 'int'>, {'A': 1, 'B': 2})}

CodePudding user response：

Try this

data = [
    { "2010":{'A':2,'B':3,'C':5,}},    
    { "2011":{'A':1,'B':2,}},
    {"2010":{'A':1,'B':2,}}
]

res = {}

for d in data:
    # print(d.items())
    items = list(d.items())[0]  # convert to list because dict items isn't subscriptable
    year, value = items
    if year not in res:
        res[year] = value

res is equal to

{
    '2010': {'A': 2, 'B': 3, 'C': 5},
    '2011': {'A': 1, 'B': 2}
}

CodePudding user response：

you can use .get() like below.

Try this:

data = [
    {"2010" : {'A' : 2,'B' : 3,'C' : 5,}},    
    {"2011" : {'A' : 1,'B' : 2,}},
    {"2010" : {'A' : 1,'B' : 2,}}
]

dct = {}
for d in data:
    for k,v in d.items():
        dct[k] = dct.get(k,{})
        for k2,v2 in v.items():
            dct[k][k2] = dct[k].get(k2,0)   v2
            
print(dct)

Otput:

{'2010': {'A': 3, 'B': 5, 'C': 5}, '2011': {'A': 1, 'B': 2}}