Make a 4d numpy array into a list of 3d numpy arrays

Question

I have a numpy array of shape (30, 100, 28, 28) - 30 batches of 100 instances of 28x28. I would like to split this 4d numpy array into a list of length 30. In this list every element would be a numpy array of shape (100, 28, 28). How can I do that?

[SO]: How to create a Minimal, Reproducible Example (reprex (mcve)). Did you try a list comprehension that simply iterates on the 4D array? Your request is (at least) odd as the (4D) NumPy array offers the same interface (and more) as the resulting list. — CristiFati
– CristiFati, Commented Apr 9, 2022 at 10:45

Black Raven · Accepted Answer · 2022-04-09 10:48:32Z

1

First, you can already consider it as a list, without converting it at all, you can iterate through it or do everything you can do with a list.

But if you really want a list, all you have to do is to pass it in the list constructor :

>>> m = np.zeros((30,100,28,28))
>>> m.shape
(30,100,28,28)
>>> l = list(m)
>>> type(l[0])
<class 'numpy.ndarray'>
>>> l[0].shape
(100, 28, 28)
>>> len(l)
30

l is your splitted list

answered Apr 9, 2022 at 10:48

Black Raven

1545 bronze badges

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

Collectives™ on Stack Overflow

Make a 4d numpy array into a list of 3d numpy arrays

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related