Perhaps the error message is somewhat misleading, but the gist is that X_train is a list, not a numpy array. You cannot use array indexing on it. Make it an array first:
out_images = np.array(X_train)[indices.astype(int)]
I get this error whenever I use np.concatenate the wrong way:
>>> a = np.eye(2)
>>> np.concatenate(a, a)
Traceback (most recent call last):
File “
File “<__array_function__ internals>“, line 6, in concatenate
TypeError: only integer scalar arrays can be converted to a scalar index
The correct way is to input the two arrays as a tuple:
>>> np.concatenate((a, a))
array([[1., 0.],
[0., 1.],
[1., 0.],
[0., 1.]])