How to reshape an array in Python using Numpy?

Question

I have a (10,) array I want to reshape in (1,10)

I did the following (u being my array)

import numpy as np

u = u.reshape(-1,1).T

but it does not work, any advice ?

Possible duplicate of [What does -1 mean in numpy reshape?](https://stackoverflow.com/questions/18691084/what-does-1-mean-in-numpy-reshape) — Chris, Apr 04 '19 at 08:03

score 3 · Answer 1 · answered Apr 04 '19 at 08:19

3

As mentioned by Chris in his comment you simply want to reshape the array by fixing the number of rows to one and let Python figure out the other dimension:

u=u.reshape(1, -1)

answered Apr 04 '19 at 08:19

CAPSLOCK

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score 3 · Answer 2 · answered Apr 04 '19 at 08:32

I think @Chris has mentioned well in the comment, you can try out

I have tried out the scenario

>>> import numpy as np
>>> u = np.zeros((10))

>>> u.shape
(10,)
>>> u.T
array([0., 0., 0., 0., 0., 0., 0., 0., 0., 0.])
>>> u = u.reshape(1, -1)
>>> u.shape
(1, 10)
>>> u.T
array([[0.],
   [0.],
   [0.],
   [0.],
   [0.],
   [0.],
   [0.],
   [0.],
   [0.],
   [0.]])

I think for your case u.reshape(1, -1) would do your work.

score 2 · Answer 3 · answered Apr 04 '19 at 08:06

2

You can try to use expand_dims() method.

import numpy as np

a = np.zeros(10) # a.shape = (10,)
a = np.expand_dims(a, axis=0)
print(a.shape)

Output

(1, 10)

answered Apr 04 '19 at 08:06

user3053452

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score 1 · Answer 4 · answered Apr 04 '19 at 08:11

1

What you want is :

u = u.reshape((-1, 1)).T

answered Apr 04 '19 at 08:11

sowlosc

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score 0 · Answer 5 · answered Apr 04 '19 at 08:28

0

Another trick in the book that works is with np.newaxis

 u = u[np.newaxis,:]

Should give you an array with shape (1,10)

answered Apr 04 '19 at 08:28

Ash Sharma

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How to reshape an array in Python using Numpy?

5 Answers5