How to “scale” a numpy array?

Question

I would like to scale an array of shape (h, w) by a factor of n, resulting in an array of shape (h*n, w*n), with the.

Say that I have a 2x2 array:

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Answer 1

scipy.misc.imresize can scale images. It can be used to scale numpy arrays, too:

#!/usr/bin/env python

import numpy as np
import scipy.misc

def scale_array(x, new_size):
    min_el = np.min(x)
    max_el = np.max(x)
    y = scipy.misc.imresize(x, new_size, mode='L', interp='nearest')
    y = y / 255 * (max_el - min_el) + min_el
    return y

x = np.array([[1, 1],
              [0, 1]])
n = 2
new_size = n * np.array(x.shape)
y = scale_array(x, new_size)
print(y)