Python Program to Find the Total Sum of a Nested List

[ibreeden]

Haha @menator01 , you are cheating! It would work fine if the list would remain limited to two dimensions, but it it is't. Vlearner had a list with a deeper nesting level: [[4,5],[7,8,[20]],100]. When you run your code on this list you get:

Error:
Traceback (most recent call last):
  File "/home/ibreeden/PycharmProjects/Forum/forum02.py", line 43, in <module>
    print(sum_nested_list(mylist))
  File "/home/ibreeden/PycharmProjects/Forum/forum02.py", line 33, in sum_nested_list
    total = total + sum(num)
TypeError: unsupported operand type(s) for +: 'int' and 'list'

@vlearner : your code is almost correct, you must change line 13 to

total += sum_nested_list(l[j])

... or else you lose the result of your recursive call.

I checked this solution but I am not getting how the code works. can anyone explain the logic of code?

The algorithm is straigtforward. If you would pass a list with integers to your function, it would return the sum of the numbers. But if one of the elements of the list is again a (nested) list, then this list is handled by the (recursive) call to the same function. In that case the returned sum must be added to the total.