Python – Nested record values summation

Last Updated : 10 May, 2020

Sometimes, while working with records, we can have problem in which we need to perform summation of nested keys of a key and record the sum as key’s value. This can have possible applications in domains such as Data Science and web development. Lets discuss certain ways in which this task can be performed.

Method #1 : Using loop
This is brute force way in which we can perform this task. In this, we iterate through the nested dictionary summing up the values and assigning to respective key.

# Python3 code to demonstrate working of 
# Nested record values summation
# Using loop
  
# initializing dictionary
test_dict = {'gfg' : {'a' : 4, 'b' : 5, 'c' : 6},
             'is' : {'a': 2, 'b' : 9, 'c' : 10},
             'best' : {'a' : 10, 'b' : 2, 'c' : 12}}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Nested record values summation
# Using loop
res = dict()
for sub in test_dict:
    sum = 0
    for keys in test_dict[sub]:
        sum = sum + test_dict[sub][keys]
    res[sub] = sum
      
# printing result 
print("The dictionary after keys summation is : " + str(res)) 

Output :

The original dictionary is : {'best': {'a': 10, 'c': 12, 'b': 2}, 'is': {'a': 2, 'c': 10, 'b': 9}, 'gfg': {'a': 4, 'c': 6, 'b': 5}}
The dictionary after keys summation is : {'best': 24, 'is': 21, 'gfg': 15}

Method #2 : Using sum()
This is yet another way in which this task can be performed. In this, we perform the task of computation using sum().

# Python3 code to demonstrate working of 
# Nested record values summation
# Using sum()
from collections import Counter
  
# initializing dictionary
test_dict = {'gfg' : {'a' : 4, 'b' : 5, 'c' : 6},
             'is' : {'a': 2, 'b' : 9, 'c' : 10},
             'best' : {'a' : 10, 'b' : 2, 'c' : 12}}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Nested record values summation
# Using sum()
res = dict()
for sub in test_dict:
    res[sub] = sum([test_dict[sub][ele] for ele in test_dict[sub]])
  
# printing result 
print("The dictionary after keys summation is : " + str(dict(res))) 

Output :

The original dictionary is : {'best': {'a': 10, 'c': 12, 'b': 2}, 'is': {'a': 2, 'c': 10, 'b': 9}, 'gfg': {'a': 4, 'c': 6, 'b': 5}}
The dictionary after keys summation is : {'best': 24, 'is': 21, 'gfg': 15}

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Python – Nested record values summation