import numpy as np

x = np.matrix([[1,2,3], [4,5,6]])
y = np.matrix([1,2,3,4,5,6])
# x[1,1]返回行下标和列下标都为1的元素
# 注意，对于矩阵x来说，x[1,1]和x[1][1]的含义不一样
print(x, y, x[1,1], sep='\n\n')