如何在numpy数组形状（n，）或（n，1）中旋转数字？

Question

Say I have a numpy array: 说我有一个numpy数组：

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

and I want to "rotate" it to get: 我想“旋转”它得到：

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

What is the best way? 什么是最好的方法？

I have been converting to a deque and back (see below) but is there a better way? 我一直在转换到一个双端队列并且回来（见下文）但是有更好的方法吗？

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

Answer 1

Just use the numpy.roll function: 只需使用numpy.roll函数：

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

See also this question . 另见这个问题。

Answer 2

numpy.concatenate([a[-1:], a[:-1]])
>>> array([4, 0, 1, 2, 3])

Answer 3

试试这个吧

b = a[-1:]+a[:-1]