Python Error ValueError could not broadcast input array from shape 4 into shape 1000

Question

I have the following python code:

big_array = np.zeros(shape=(100,100), dtype=np.uint8) 
mini_square = np.ones(shape=(2,2), dtype=np.uint8) 

flattened_array = np.ravel(big_array) 
flattened_minisquare = np.ravel(mini_square) 

flattened_array[1:-1:10] = flattened_minisquare

I get the following error:

"ValueError: could not broadcast input array from shape (4) into shape (1000)"

Comments

What exactly are you trying to do?

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I'm trying to insert a small array into a larger one without resizing.

Answer 1

There are better ways of achieving the same. Have a look at this:

import numpy as np

big_array = np.zeros(shape=(100,100), dtype=np.uint8)
mini_square = np.ones(shape=(2,2), dtype=np.uint8) 

flattened_array = np.ravel(big_array)
flattened_minisquare = np.ravel(mini_square)

stepsize = 10
temp = np.zeros(stepsize + len(flattened_minisquare) - 1)
temp[-len(flattened_minisquare):] = flattened_minisquare

mask = np.copy(temp)
mask[-len(flattened_minisquare):] = np.ones_like(flattened_minisquare)
mask = ~mask.astype(bool)

out = np.resize(temp, len(flattened_array))
final_mask = np.resize(mask, len(flattened_array))
out[final_mask] = flattened_array[final_mask]

print(out)
#[0. 0. 0. ... 0. 0. 0.]

Hope this helps!

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Thanks!