How to increase plus 2 all elements of lists ?

Question

My code is:

m=[[1,2,3], [4,5,6],[7,8,9]]
print([r[0] + 2 for r in m]

but it will increase only 1 element from every list

Answer 1

this can be done with 2 nested loops and an enumerator for the index:

nums = [[1,2,3], [4,5,6],[7,8,9]]
for lst in nums:
for index, num in enumerate(lst):
lst[index] = num +2
print(nums)

# result is: [[3, 4, 5], [6, 7, 8], [9, 10, 11]]

Answer 2

m = [[1,2,3], [4,5,6], [7,8,9]]
m = [[*map(lambda el: el+2, el)] for el in m]
print(m)

Answer 3

Lothar , thanks. Fixed.

Answer 4

m=[[1,2,3],[4,5,6],[7,8,9]]

n=[]
for i in m:
k=[]
for j in i:
k+=[j+2]
n+=[k]
print(n)

Answer 5

Thank You all :)

Answer 6

Check the performance of different ways of doing it as suggested by people here,

The first one is the code I came up with(similar to one by Vitaly) which is a little expensive

https://code.sololearn.com/c8JJsWQOs0FO/?ref=app

Lastly the best implementation will depend based on large input size but still I just wanted to see how they perform