Dividing numpy 2D array into finer resolution

Question

I have a 2d numpy array (2 x 2) elements, I want to create another 2D numpy array out of it, such that:

2D array:

import numpy as np
np.random.rand(2,2)

  array([[10.0,8.0],
              [6.0,4.0]])

I want to get a 4x4 array out of it such that all values of the finer resolution array corresponding to a specific cell of the coarser array, are the same as the coarser array:

  array([[10.0,10.0,8.0,8.0],
            [10.0,10.0,8.0,8.0]
            [6.0,6.0,4.0,4.0]
            [6.0,6.0,4.0,4.0]])

I could do this using for loops, but would really like to find out if a more pythonic way exists.

fjarri · Accepted Answer · 2015-09-08 00:40:06Z

3

You can use repeat:

>>> a = np.random.rand(2,2)
>>> a
array([[ 0.66172561,  0.09262421],
       [ 0.40578266,  0.84510431]])
>>> a.repeat(2, 0).repeat(2, 1)
array([[ 0.66172561,  0.66172561,  0.09262421,  0.09262421],
       [ 0.66172561,  0.66172561,  0.09262421,  0.09262421],
       [ 0.40578266,  0.40578266,  0.84510431,  0.84510431],
       [ 0.40578266,  0.40578266,  0.84510431,  0.84510431]])

answered Sep 8, 2015 at 0:40

fjarri

9,74645 silver badges52 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

user308827 Over a year ago

Can your soln be extended to converting a 2x2 nump array to a 8x8 array?

fjarri Over a year ago

Yes, first argument is the number of repetitions, the second argument is the axis. Array size does not matter.

user308827 Over a year ago

great, this is super useful

Collectives™ on Stack Overflow

Dividing numpy 2D array into finer resolution

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related