python numpy 矩阵创建

1. 创建一般的多维数组

import numpy as np

a = np.array([1,2,3], dtype=int)

type(a)

a.shape

a.dtype.name

a.size

a.itemsize

b=np.array([1,2,3],[4,5,6], dtype=int)

b.shape

b.size

b.itemsize

c = np.ones((2,3,4), dtype = np.int16)

2.

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

[[10,11,12],[13,14,15],[16,17,18]],

[[19,20,21],[22,23,24],[25,26,27]]]

a = np.array(

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

[[10,11,12],[13,14,15],[16,17,18]],

[[19,20,21],[22,23,24],[25,26,27]]]

)

a[: , : , ::-1]

b= np.array(

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

[[10,11,12,0,0],[13,14,15,0,0],[16,17,18,0,0]],

[[19,20,21,0,0],[22,23,24,0,0],[25,26,27,0,0]],

[[28,29,30,0,0],[31,32,33,0,0],[34,35,36,0,0]]

]

)