Python Counter sum function: Add two counter objects

Last update on April 23 2025 12:50:58 (UTC/GMT +8 hours)

6. Sum of Two Counters

Write a function that takes two 'Counter' objects and returns their sum.

Sample Solution:

Code:

from collections import Counter

def add_counters(ctr1, ctr2):
    return ctr1 + ctr2

def main():
    counter1 = Counter({'item1': 10, 'item2': 34, 'item3': 22})
    counter2 = Counter({'item1': 12, 'item2': 20, 'item3': 10})
    
    result_counter = add_counters(counter1, counter2)
    
    print("Counter 1:", counter1)
    print("Counter 2:", counter2)
    print("Sum Counter:", result_counter)

if __name__ == "__main__":
    main()

Output:

Counter 1: Counter({'item2': 34, 'item3': 22, 'item1': 10})
Counter 2: Counter({'item2': 20, 'item1': 12, 'item3': 10})
Sum Counter: Counter({'item2': 54, 'item3': 32, 'item1': 22})

In the exercise above, the "add_counters()" function takes two "Counter" objects as input and returns their sum. By using the '+' operator, both counters are added element-by-element, which combines the common and unique counts of both counters.

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python function that takes two Counter objects, returns their sum, and then prints the resulting counts.
Write a Python script to merge two Counters by adding counts for duplicate keys and output the merged Counter in sorted order.
Write a Python program to sum two Counter objects and verify the result by comparing it with manual summation of counts.
Write a Python function that accepts two Counters, sums them, and then displays keys with their combined counts in descending order.

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