转置3-D Numpy数组

Question

Suppose I have a numpy array A with shape (5,24,1) .
I want to take five separate transposes along axis = 0 , such that the resulting shape after transposes is (5,1,24) .
How can I do this using some of the numpy functions?

Answer 1

Three approaches could be suggested -

A.swapaxes(1,2)
A.transpose(0,2,1)
np.rollaxis(A,2,1)

For swapaxes and transpose , please follow their docs.

With np.rollaxis , we are rolling the axes to bring the third axis into the second position and thus pushing back the second axis into third axis position. More info in the linked docs.

Using the fact that the last axis is singleton -

A[:,None,:,0]

Answer 2

You could use np.moveaxis (one option missing from Divakars excellent answer) where you can define which axis should be moved:

np.moveaxis(A, (0, 1, 2), (0, 2, 1))

This moves axis 0 to 0 (no change, could also be omitted), 1 to 2 and 2 to 1 . So this basically just swaps axis 1 and 2.

>>> A = np.ones((5,24,1))
>>> res = np.moveaxis(A, (1, 2), (2, 1))   # this time without the zeros
>>> res.shape
(5, 1, 24)