CODEWITHSUNDEEP
pythonlistmultidimensional-array
miniplanck
miniplanck

Reputation: 79

Summing list of lists with another list of lists in Python

Let's say I have two lists of lists, a and b:

a = [[1,2,3],[4,5,6]]

b = [[7,8,9],[1,2,3]]

If a and b were both lists of numbers, I could just convert them to arrays and obtain the sum a+b using Python. However, it seems I am unable to do the same if a and b are lists of lists. Is there a similar method, without using for or while cicles?

Edit The desired result would be [[8,10,12],[5,7,9]]

Upvotes: 0

Views: 75

Answers (2)

Sushil
Sushil

Reputation: 131

List compression:

[[a + b for a, b in zip(x, y)]for x, y in zip(a, b)]

Another way:

k = []
for x, y in zip(a, b):
    p = []
    for a, b in zip(x, y):
        p.append(a + b)
    k.append(p)
print(k)

Upvotes: 1

seric sheon
seric sheon

Reputation: 95

import numpy as np
a = [[1,2,3],[4,5,6]]

b = [[7,8,9],[1,2,3]]

a=np.array(a)
a=a.flatten()
b=np.array(b)
b=b.flatten()
c=np.add(a,b)
print(a)
print(b)
print(c)
output:
a=[1 2 3 4 5 6]
b=[7 8 9 1 2 3]
c=[ 8 10 12  5  7  9]

after this if you want list of list you can reshape it like:

c=np.reshape(c,[2,3])

Upvotes: 1

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