如何在python中移动2D numpy数组？

Question

如何在Python中移动2D numpy数组的元素？

例如，转换此数组：

[[ 1, 2, 3],
[ 4, 5, 6],
[ 7, 8, 9],
[10, 11, 12]]

此数组：

[[0, 0, 0,],
[ 1, 2, 3],
[ 4, 5, 6],
[ 7, 8, 9]]

Answer 1

我要手动进行切片，这是切片的工作方式：

import numpy as np

A = np.array([[ 1, 2, 3],
              [ 4, 5, 6],
              [ 7, 8, 9],
              [10, 11, 12]])

A[1:,:] = A[:3,:]
A[:1,:] = [0, 0, 0]

Answer 2

import numpy as np
a = np.array([[ 1, 2, 3],
              [ 4, 5, 6],
              [ 7, 8, 9],
              [10, 11, 12]])    

def shift_array(array, place):
    new_arr = np.roll(array, place, axis=0)
    new_arr[:place] = np.zeros((new_arr[:place].shape))
    return new_arr

shift_array(a,2)

# array([[ 0,  0,  0],
#        [ 0,  0,  0],
#        [ 1,  2,  3],
#        [ 4,  5, 6]])