How do you rotate the numbers in an numpy array of shape (n,) or (n,1)?

Question

Say I have a numpy array:

>>> a 
array([0,1,2,3,4])

and I want to "rotate" it to get:

>>> b
array([4,0,1,2,3])

What is the best way?

I have been converting to a deque and back (see below) but is there a better way?

b = deque(a)
b.rotate(1)
b = np.array(b)

Answer 1

Just use the numpy.roll function:

a = np.array([0,1,2,3,4])
b = np.roll(a,1)
print(b)
>>> [4 0 1 2 3]

See also this question.