切片索引

一维度数组的切片索引

import numpy as np
# 创建一个一维数组
arr = np.arange(5)
print ('arr数组：', arr)
# 切片获取数据，从下标索引值为3到结束的切片
print ('arrp[3:]的数据：', arr[3:])

arrp[3:]的数据： [3 4]

二维度数组的切片索引

# 创建一个二维数组
arr2d = np.array([[1,2,3],
                               [4,5,6],
                               [7,8,9]])
print ('arr2d数组：\n', arr2d)

# 输出切片数据
print ('arr2d[:2,1:]的切片：\n', arr2d[:2,1:])
print ('arr2d[1,:2]的切片：\n', arr2d[1,:2])
print ('arr2d[2,:1]的切片：\n', arr2d[2,:1])
print ('arr2d[:,:1]的切片：\n', arr2d[:,:1])

arr2d数组：
[[1 2 3]
[4 5 6]
[7 8 9]]
arr2d[:2,1:]的切片：
[[2 3]
[5 6]]
arr2d[1,:2]的切片：
[4 5]
arr2d[2,:1]的切片：
[7]
arr2d[:,:1]的切片：
[[1]
[4]
[7]]

三维度数组切片索引