# Python Program to Find the Total Sum of a Nested List Using Recursion

When it is required to find the total sum of a nest list using the recursion technique, a user defined method is used, that takes the list as a parameter.

The recursion computes output of small bits of the bigger problem, and combines these bits to give the solution to the bigger problem.

A list can be used to store heterogeneous values (i.e data of any data type like integer, floating point, strings, and so on).

## Example

Below is a demonstration for the same −

Live Demo

def recursion_sum(my_list):
my_total = 0
for elem in my_list:
if (type(elem) == type([])):
my_total = my_total + recursion_sum(elem)
else:
my_total = my_total + elem
return my_total
my_list = [[2,3], [7,9], [11,45], [78,98]]
print("The list elements are :")
print(my_list)
print( "The sum is :")
print(recursion_sum(my_list))

## Output

The list elements are :
[[2, 3], [7, 9], [11, 45], [78, 98]]
The sum is :
253

## Explanation

• A method named ‘recursion_sum’ is defined, with list as a paramteter.
• Initially, a variable is assigned to 0.
• The elements in the list are iterated over, and if their type matches, the elements in the list are added, and the method is called again.
• Otherwise, the elements are just added to a variable.
• This variable is displayed as output on the console.
• Outside the function, the below operations take place −
• The nested list is defined, and is displayed on the console.
• The method is called by passing this list as a parameter.
• The output is displayed on the console.