Python sum list of lists | Example code

Use sum() function with a generator expression to get sum list of lists in Python.

``sum(sum(x) for x in list)``

Python sum list of lists example

Simple example code.

``````lis = [[1, 2], [3, 4], [5, 6]]

res = sum(sum(x) for x in lis)

print("Sum list of lists:", res)``````

Output:

Sum of list of lists and returns sum list

``````[[3,7,2],
[1,4,5],
[9,8,7]]
_______
>>>[13,19,14]``````

This uses a combination of `zip` and `*` to unpack the list and then zip the items according to their index. You then use a list comprehension to iterate through the groups of similar indices, summing them and returning in their ‘original’ position.

``````l = [[3, 7, 2], [1, 4, 5], [9, 8, 7]]

res = [sum(i) for i in zip(*l)]

print(res)``````

Output: [13, 19, 14]

Do comment if you have any doubts or suggestions on this Python sum topic.

Note: IDE: PyCharm 2021.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.

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