Reputation: 2785

How to transpose a 2 Element Vector

In python, I have a 2x1 array

a=array([[ 0,  4,  8, 12, 16],
     [ 0,  8, 16, 24, 32]])

When I extract a column vector

c=a[:,1]

C becomes a 1x2 array, and I wish it to be a 2x1 array. Applying transpose does not seems to do the trick.

Any suggestions?

Thanks

Upvotes: 1

Answers (3)

Reputation: 68682

Other options include:

import numpy as np
c = a[:,1]

and then access the data with the desired shape using:

c[:,np.newaxis]

c[:,None]

Upvotes: 1

Reputation: 212885

After

c=a[:,1]

c is now:

array([4, 8])

i.e. a 1D array (so even not 1x2).

If you want it a 2x1 array, try this:

c = a[:,1:2]

it will become:

array([[4],
       [8]])

Upvotes: 8

Reputation: 33397

Have you tried c.reshape(2,1) ?

Upvotes: 1