Python 如何在numpy中进行循环移位
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how to do circular shift in numpy
提问by LWZ
I have a numpy array, for example
例如，我有一个 numpy 数组
a = np.arange(10)
how can I move the first nelements to the end of the array?
如何将第一个n元素移动到数组的末尾？
I found this rollfunction but it seems like it only does the opposite, which shifts the last nelements to the beginning.
我找到了这个roll函数，但它似乎只做相反的事情，将最后一个n元素移到开头。
采纳答案by mgilson
Why not just rollwith a negative number?
为什么不只是roll一个负数？
>>> import numpy as np
>>> a = np.arange(10)
>>> np.roll(a,2)
array([8, 9, 0, 1, 2, 3, 4, 5, 6, 7])
>>> np.roll(a,-2)
array([2, 3, 4, 5, 6, 7, 8, 9, 0, 1])
回答by Francesco Montesano
you can use negative shift
你可以使用负移
a = np.arange(10)
print(np.roll(a, 3))
print(np.roll(a, -3))
returns
返回
[7, 8, 9, 0, 1, 2, 3, 4, 5, 6]
[3, 4, 5, 6, 7, 8, 9, 0, 1, 2]
[7, 8, 9, 0, 1, 2, 3, 4, 5, 6]
[3, 4, 5, 6, 7, 8, 9, 0, 1, 2]
