Python | Ways to sum list of lists and return sum list
List is an important container and used almost in every code of day-day programming as well as web-development, more it is used, more is the requirement to master it and hence knowledge of its operations is necessary. Given a list of lists, the program to suppose to return the sum as final list.
Let’s see some of the methods to sum list of list and return list.
Method # 1: Using Naive method
# Python code to demonstrate # sum of list of list # using naive method # Declaring initial list of list L = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] # Printing list of list print("Initial List - ", str(L)) # Using naive method res = list() for j in range(0, len(L[0])): tmp = 0 for i in range(0, len(L)): tmp = tmp + L[i][j] res.append(tmp) # printing result print("final list - ", str(res)) |
chevron_right
filter_none
Output:
Initial List - [[1, 2, 3], [4, 5, 6], [7, 8, 9]] final list - [12, 15, 18]
Method #2: Using numpy array
A numpy is a general-purpose array-processing package. It provides a high-performance multidimensional array object, and tools for working with these arrays.
# Pyhton code to demonstrate # sum of list of list # using numpy array functions import numpy as np # Declaring initial list of list List = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]) # Printing list of list print("Initial List - ", str(List)) # Using numpy sum res = np.sum(List, 0) # printing result print("final list - ", str(res)) |
chevron_right
filter_none
Output:
Initial List - [[1 2 3]
[4 5 6]
[7 8 9]]
final list - [12 15 18]
Method #3: Using zip() and list comprehension
# Pyhton code to demonstrate # sum of list of list using # zip and list comprehension # Declaring initial list of list List = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] # Printing list of list print("Initial List - ", str(List)) # Using list comprehension res = [sum(i) for i in zip(*List)] # printing result print("final list - ", str(res)) |
chevron_right
filter_none
Output:
Initial List - [[1, 2, 3], [4, 5, 6], [7, 8, 9]] final list - [12, 15, 18]
Recommended Posts:
- Python | Ways to iterate tuple list of lists
- Python | Sorting list of lists with similar list elements
- Python | Check if a list exists in given list of lists
- Python | Maximum sum of elements of list in a list of lists
- Python | Convert list into list of lists
- Python | Return new list on element insertion
- Python | Program to count number of lists in a list of lists
- Python | Ways to shuffle a list
- Python | Ways to flatten a 2D list
- Different ways to clear a list in Python
- Python | Ways to rotate a list
- Python | Ways to Spilt the list by some value
- Extending a list in Python (5 different ways)
- Python | Split list into lists by particular value
- Python | Multiply all numbers in the list (3 different ways)
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.
