Python | Get sum of tuples having same first value

Given a list of tuple, the task is to sum the tuples having same first value.

Examples:

Input: [(1, 13), (2, 190), (3, 82), (1, 12)]
Output: [(1, 25), (2, 190), (3, 82)]

Input: [(1, 13), (1, 190), (3, 25), (1, 12)]
Output: [(1, 215), (3, 25)]

Let’s discuss the different ways we can do this task.

Method #1: Using map()

# Python code to get sum of tuples having same first value 
  
# Initialisation of list of tuple 
Input = [(1, 13), (1, 190), (3, 25), (1, 12)] 
  
d = {x:0 for x, _ in Input} 
  
for name, num in Input: d[name] += num 
  
# using map 
Output = list(map(tuple, d.items())) 
  
# printing output 
print(Output) 

Output:

[(1, 215), (3, 25)]

Method #2: Using defaultdict

# Python code to sum list of tuples having same first value 
  
# Importing 
from collections import defaultdict 
  
# Initialisation of list of tuple 
Input = [(2, 190), (1, 13), (1, 12),  
         (2, 14), (3, 82), (1, 70)] 
  
# Initialisation of defaultdict 
output = defaultdict(int) 
  
for k, v in Input: 
    output[k] += v 
  
# Printing output 
print(list(output.items())) 

Output:

[(1, 95), (2, 204), (3, 82)]

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