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Python – Multiple Keys Grouped Summation

  • Last Updated : 06 Jul, 2021

Sometimes, while working with Python records, we can have a problem in which, we need to perform elements grouping based on multiple key equality, and also summation of the grouped result of particular key. This kind of problem can occur in application in data domains. Let’s discuss certain way in which this task can be performed.

Input
test_list = [(12, ‘M’, ‘Gfg’), (23, ‘H’, ‘Gfg’), (13, ‘M’, ‘Best’)] 
grp_indx = [1, 2] [ Indices to group ] 
sum_idx = [0] [ Index to sum ] 
Output : [(‘M’, ‘Gfg’, 12), (‘H’, ‘Gfg’, 23), (‘M’, ‘Best’, 13)]

Input
test_list = [(12, ‘M’, ‘Gfg’), (23, ‘M’, ‘Gfg’), (13, ‘M’, ‘Best’)] 
grp_indx = [1, 2] [ Indices to group ] 
sum_idx = [0] [ Index to sum ] 
Output : [(‘M’, ‘Gfg’, 35), (‘M’, ‘Best’, 13)] 
 

Method : Using loop + defaultdict() + list comprehension 
The combination of above functionalities can be used to solve this problem. In this, we perform grouping using loop and the task of performing summation of key is done using list comprehension.

Python3




# Python3 code to demonstrate working of
# Multiple Keys Grouped Summation
# Using loop + defaultdict() + list comprehension
from collections import defaultdict
 
# initializing list
test_list = [(12, 'M', 'Gfg'), (23, 'H', 'Gfg'),
            (13, 'M', 'Best'), (18, 'M', 'Gfg'),
            (2, 'H', 'Gfg'), (23, 'M', 'Best')]
 
# printing original list
print("The original list is : " + str(test_list))
 
# initializing grouping indices
grp_indx = [1, 2]
 
# initializing sum index
sum_idx = [0]
 
# Multiple Keys Grouped Summation
# Using loop + defaultdict() + list comprehension
temp = defaultdict(int)
for sub in test_list:
    temp[(sub[grp_indx[0]], sub[grp_indx[1]])] += sub[sum_idx[0]]
res = [key + (val, ) for key, val in temp.items()]
                 
# printing result
print("The grouped summation : " + str(res))
Output : 
The original list is : [(12, ‘M’, ‘Gfg’), (23, ‘H’, ‘Gfg’), (13, ‘M’, ‘Best’), (18, ‘M’, ‘Gfg’), (2, ‘H’, ‘Gfg’), (23, ‘M’, ‘Best’)] 
The grouped summation : [(‘M’, ‘Gfg’, 30), (‘H’, ‘Gfg’, 25), (‘M’, ‘Best’, 36)] 
 

 
 


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