import numpy as np

A = np.arange(3,15)

print('-1-')

print(A)

print('-2-')

print(A[3])

A = np.arange(3,15).reshape((3,4))

print('-3-')

print(A[1])

print('-4-')

print(A[2][1])

# 第一行和第二行

print('-5-')

print(A[1:3])

print('-6-')

for row in A:

    print (row)

print('-7-')

for column in A.T:

    print (column)

print('-8-')

for item in A.flat:

    print (item)

# 迭代器

print('-9-')

print(A.flat)

# 展成一行

print('-10-')

print(A.flatten())

A = np.array([1,1,1])

B = np.array([2,2,2])

# 上下合并

print('-11-')

print(np.vstack((A,B)))

C = np.vstack((A,B))

print('-12-')

print(A.shape, C.shape)

# 左右合并

D = np.hstack((A,B))

print('-13-')

print(D)

print('-14-')

print(A.shape, D.shape)

#横向的数列转化到列，行向加维度

print('-15-')

print(A[np.newaxis,:])

#纵向的数列转化到行，纵向的添加维度

print('-16-')

print(A[:,np.newaxis])

A = np.array([1,1,1])[:,np.newaxis]

B = np.array([2,2,2])[:,np.newaxis]

# 三个向量的横向合并

print('-17-')

print(np.hstack((A,A,B)))

# 三个向量的竖向合并

C = np.concatenate((A,B,B,A))

print('-18-')

print(C)

# 三个向量的竖向合并

C = np.concatenate((A,B,B,A), axis=0)

print('-19-')

print(C)

# 三个向量的横向合并

C = np.concatenate((A,B,B,A), axis=1)

print('-20-')

print(C)

A = np.arange(12).reshape((3,4))

print('-21-')

print(A)

#分成两块，按列划分，只能进行相等的划分

print('-22-')

print(np.split(A,2,axis = 1))

print('-23-')

print(np.split(A,3,axis = 0))

#分成两块，按列划分，进行不相等的划分

print('-24-')

print(np.array_split(A,3,axis = 1))

# 垂直划分

print('-25-')

print(np.vsplit(A,3))

# 竖直划分

print('-26-')

print(np.hsplit(A,2))

a=np.arange(4)

b = a # 引用复制

c = a # abcd都是一样

d = a

a[0] = 11

print('-27-')

print(b,c,d) # 都是11

d is a

e = a.copy() # deep copy

-1-

[ 3  4  5  6  7  8  9 10 11 12 13 14]

-2-

6

-3-

[ 7  8  9 10]

-4-

12

-5-

[[ 7  8  9 10]

 [11 12 13 14]]

-6-

[3 4 5 6]

[ 7  8  9 10]

[11 12 13 14]

-7-

[ 3  7 11]

[ 4  8 12]

[ 5  9 13]

[ 6 10 14]

-8-

3

4

5

6

7

8

9

10

11

12

13

14

-9-

<numpy.flatiter object at 0x000002A6F47AB7B0>

-10-

[ 3  4  5  6  7  8  9 10 11 12 13 14]

-11-

[[1 1 1]

 [2 2 2]]

-12-

(3,) (2, 3)

-13-

[1 1 1 2 2 2]

-14-

(3,) (6,)

-15-

[[1 1 1]]

-16-

[[1]

 [1]

 [1]]

-17-

[[1 1 2]

 [1 1 2]

 [1 1 2]]

-18-

[[1]

 [1]

 [1]

 [2]

 [2]

 [2]

 [2]

 [2]

 [2]

 [1]

 [1]

 [1]]

-19-

[[1]

 [1]

 [1]

 [2]

 [2]

 [2]

 [2]

 [2]

 [2]

 [1]

 [1]

 [1]]

-20-

[[1 2 2 1]

 [1 2 2 1]

 [1 2 2 1]]

-21-

[[ 0  1  2  3]

 [ 4  5  6  7]

 [ 8  9 10 11]]

-22-

[array([[0, 1],

       [4, 5],

       [8, 9]]), array([[ 2,  3],

       [ 6,  7],

       [10, 11]])]

-23-

[array([[0, 1, 2, 3]]), array([[4, 5, 6, 7]]), array([[ 8,

9, 10, 11]])]

-24-

[array([[0, 1],

       [4, 5],

       [8, 9]]), array([[ 2],

       [ 6],

       [10]]), array([[ 3],

       [ 7],

       [11]])]

-25-

[array([[0, 1, 2, 3]]), array([[4, 5, 6, 7]]), array([[ 8,

9, 10, 11]])]

-26-

[array([[0, 1],

       [4, 5],

       [8, 9]]), array([[ 2,  3],

       [ 6,  7],

       [10, 11]])]

-27-

[11  1  2  3] [11  1  2  3] [11  1  2  3]