Python Data Structures and Algorithms - Recursion: List sum

Last update on March 27 2025 12:50:24 (UTC/GMT +8 hours)

3. Sum of Nested Lists Using Recursion

Write a Python program to sum recursion lists using recursion.

Sample Solution:

Python Code:

# Define a function named recursive_list_sum that calculates the sum of elements in a nested list
def recursive_list_sum(data_list):
    # Initialize a variable 'total' to store the cumulative sum
    total = 0
    
    # Iterate through each element in the input list
    for element in data_list:
        # Check if the current element is a list (nested list)
        if type(element) == type([]):
            # If the element is a list, recursively call the recursive_list_sum function on the element
            total = total + recursive_list_sum(element)
        else:
            # If the element is not a list, add its value to the total
            total = total + element

    # Return the total sum
    return total

# Print the result of calling the recursive_list_sum function with the input list [1, 2, [3,4], [5,6]]
print(recursive_list_sum([1, 2, [3, 4], [5, 6]]))

Sample Output:

21

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to recursively compute the sum of all numbers in a nested list structure.
• Write a Python program to implement a recursive function that flattens a nested list and returns the total sum.
• Write a Python program to traverse a list with arbitrary nesting and sum all its integer elements using recursion.
• Write a Python program to use recursion to sum elements in a list where some elements are lists themselves.

Python Code Editor:

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