sum values base duplicate values in dict

I have a dict as below:

dict_data = {
  "NAME": ['A', 'B', 'A', 'B', 'C', 'C'],
  "VALUE": [100, 200 , 100 , 200, 300, 300]
}

How to sum values from above dict if NAME duplicate output:

NAME: A
VALUE: 200
NAME: B
VALUE: 400
NAME: C
VALUE: 600

or output to with list:

[A, B, C]
[200, 400, 600]

CodePudding user response：

Use a collections.defaultdict then iterate and sum by grouping on key

dict_data = {"NAME": ["A", "B", "A", "B", "C", "C"], "VALUE": [100, 200, 100, 200, 300, 300]}
from collections import defaultdict

result = defaultdict(int)
for key, value in zip(dict_data['NAME'], dict_data['VALUE']):
    result[key]  = value

for key, value in result.items():
    print("NAME", key)
    print("VALUE", value)

keys, values = zip(*result.items())
print(keys)
print(values)

NAME A
VALUE 200
NAME B
VALUE 400
NAME C
VALUE 600

('A', 'B', 'C')
(200, 400, 600)

CodePudding user response：

You can use defaultdict with zero in start.

dict_data = {
  "NAME": ['A', 'B', 'A' , 'B' , 'C' , 'C'],
  "VALUE": [100, 200 , 100 , 200, 300, 300]
}

from collections import defaultdict

# res = defaultdict(lambda : 0)
res = defaultdict(int)

for k,v in zip(dict_data['NAME'], dict_data['VALUE']):
    res[k]  = v
    
print(list(res.keys()))
print(list(res.values()))

Output:

['A', 'B', 'C']
[200, 400, 600]

CodePudding user response：

Without extra imports.

Use class method fromkeys to set default values

d = dict.fromkeys(dict_data['NAME'], 0)
for k, v in zip(dict_data['NAME'], dict_data['VALUE']):
    d[k]  = v

print(d)

or, more verbosely, with the instance method setdefault

d = {}
for k, v in zip(dict_data['NAME'], dict_data['VALUE']):
    d.setdefault(k, 0)
    d[k]  = v

These solutions are meant to reply to the comment "If you don't use defualtdict, you can not wtite res[k] = v"