CODEWITHSUNDEEP
python
dtups
dtups

Reputation: 11

How do I sum a list of dictionaries by key?

I have a list of dictionaries. Each dictionary is a different size and can have different and similar key names.

aList = [{
    'Hits': 3,
    'Blues': 4,
    'Classical': 6,
    'Metal': 8,
    'Rock': 4,
    'Funk': 5,
    'Hip Hop': 5,
    'Rap': 9,
    'Easy Listening': 3
}, {
    'Rap': 10,
    'Jazz': 4,
    'Hip Hop': 6,
    'Dance': 3,
    'Classical': 9,
    'Blues': 3,
    'Opera': 9,
    'Easy Listening': 3,
    'Country': 9,
    'Pop': 2,
    'Hits': 7
}, {
    'Blues': 1,
    'Metal': 9,
    'Hits': 8,
    'Dance': 2,
    'Funk': 9,
    'Jazz': 1,
    'Classical': 2
}]

How do I store the sum of all the values corresponding to each key name?

Upvotes: 1

Views: 53

Answers (3)

Induraj PR
Induraj PR

Reputation: 304

Hope this helps you.. Happy coding :)

import pandas as pd
df = pd.DataFrame(columns=['musics','value'])

index=0
for ele in aList:
  for i,k in ele.items():
      df.loc[index] = [i,k]
      index+=1

grped_df = df.groupby('musics').sum().sort_values('musics')
print(grped_df)

enter image description here

Upvotes: 0

Edwin Jarvis
Edwin Jarvis

Reputation: 144

You definitely need to use built-in Counter class from collections module. Here is working code example:

from collections import Counter

aList = [{    
    'Hits': 3,
    'Blues': 4,
    'Classical': 6,
    'Metal': 8,
    'Rock': 4,
    'Funk': 5,
    'Hip Hop': 5,
    'Rap': 9,
    'Easy Listening': 3
}, {
    'Rap': 10,
    'Jazz': 4,
    'Hip Hop': 6,
    'Dance': 3,
    'Classical': 9,
    'Blues': 3,
    'Opera': 9,
    'Easy Listening': 3,
    'Country': 9,
    'Pop': 2,
    'Hits': 7
}, {
    'Blues': 1,
    'Metal': 9,
    'Hits': 8,
    'Dance': 2,
    'Funk': 9,
    'Jazz': 1,
    'Classical': 2
}]

counter = Counter()
for d in aList:
    counter.update(d)

print(dict(counter))
# Outputs:
# {'Hits': 18, 'Blues': 8, 'Classical': 17, 'Metal': 17, 'Rock': 4, 'Funk': 14, 'Hip Hop': 11, 'Rap': 19, 'Easy Listening': 6, 'Jazz': 5, 'Dance': 5, 'Opera': 9, 'Country': 9, 'Pop': 2}

Upvotes: 2

FlorianGD
FlorianGD

Reputation: 2436

You can use collections. Counter

from collections import Counter

totals = Counter()
for elem in aList:
    totals.update(elem)
print(totals)
Counter({'Rap': 19, 'Hits': 18, 'Classical': 17, 'Metal': 17, 'Funk': 14, 'Hip Hop': 11, 'Opera': 9, 'Country': 9, 'Blues': 8, 'Easy Listening': 6, 'Jazz': 5, 'Dance': 5, 'Rock': 4, 'Pop': 2})

Upvotes: 1

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