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From: Chris Angelico <rosuav@gmail.com>
Newsgroups: comp.lang.python
Subject: Re: numpy arrays
Date: Wed, 23 Mar 2016 21:35:38 +1100
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On Wed, Mar 23, 2016 at 9:06 PM, Heli <hemla21@gmail.com> wrote:
> I have a 2D numpy array like this:
>
> [[1,2,3,4],
>  [1,2,3,4],
>  [1,2,3,4]
>  [1,2,3,4]]
>
> Is there any fast way to convert this array to
>
> [[1,1,1,1],
>  [2,2,2,2]
>  [3,3,3,3]
>  [4,4,4,4]]

What you want is called *transposing* the array:

http://docs.scipy.org/doc/numpy/reference/generated/numpy.transpose.html

That should be a sufficiently fast operation.

ChrisA