CODEWITHSUNDEEP
pythonlist
user2469761
user2469761

Reputation: 15

Merge Python List

I have a list 

a = [[1,2],[3,4],[5,6],[7,8],[9,10]]

Result

New_a = [[1,3,5,7,9],[2,4,6,8,10]]

Any smart way or python built-in function can solve the problem?

Upvotes: 0

Views: 164

Answers (3)

Akavall
Akavall

Reputation: 86168

import numpy as np
a = np.array([[1,2],[3,4],[5,6],[7,8],[9,10]])

Result:

>>> a
array([[ 1,  2],
       [ 3,  4],
       [ 5,  6],
       [ 7,  8],
       [ 9, 10]])
>>> a.T
array([[ 1,  3,  5,  7,  9],
       [ 2,  4,  6,  8, 10]])

Upvotes: 1

roippi
roippi

Reputation: 25954

list(zip(*a))
Out[6]: [(1, 3, 5, 7, 9), (2, 4, 6, 8, 10)]

Explanation: zip takes two or more iterables and stitches them together where "the i-th element comes from the i-th iterable argument." The star operator unpacks a so that you zip the elements together, not the sublists.

Upvotes: 7

Mark Reed
Mark Reed

Reputation: 95242

You can use zip in conjunction with the flattening operator *:

[list(t) for t in zip(*a)]

You could also just use zip(*a) by itself if (1) you're using Python 2 and (2) you don't mind getting a list of tuples instead of a list of lists.

Upvotes: 2

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