numpy 的简单学习（矩阵的创建，乘法运算，转置，随机生成矩阵的方法）

矫情吗；* 2022-05-12 04:36 148阅读 0赞

**numpy的一些简单小常识**

#coding = 'utf-8'
    import numpy as np
    a = np.array([2,1,4,6,3])#创建一个数组a
    print(a)
    print('=================================')
    b = np.zeros((3,4))#创建一个3*4的0元素矩阵
    print(b)
    print('=================================')
    c = np.ones((4,3))#创建一个4*3的1元素矩阵
    print(c)
    print('=================================')
    d = np.array([[1,2,3],
                  [2,3,4],
                  [3,4,5],
                  [4,5,6]])#利用array创建一个矩阵
    print(d)
    print('=================================')
    e = np.random.rand(2,4)#随机生成一个2*4的矩阵，值在（0，1）之间
    e1 = np.random.rand(4,3,2)#随机生成4个3*2的矩阵
    print(e1)
    print('**********************************')
    print(e)
    print('=================================')
    f = np.random.randn(2,4)#随机生成一个2*4的矩阵，值存在负数，具有标准正态分布的特性
    f1 = np.random.randn(5,3,2)
    print(f1)
    print('**********************************')
    print(f)
    print('=================================')
    g = np.random.randint(1,5)#生成一个1-5的随机整数
    g1 = np.random.randint(1,10,size=(10,8))#生成一个元素值位1-10之间的大小为10*8的矩阵
    print(g1)
    print('**********************************')
    print(g)
    print('随机生成[0，1）之间的浮点数')
    print('-----------random_sample--------------')
    h = np.random.random_sample(size=(3,2))
    print(h)
    print('-----------random--------------')
    h1 = np.random.random(size=(2,2))
    print(h1)
    print('-----------ranf--------------')
    h2 = np.random.ranf(size=(2,2))
    print(h2)
    print('-----------sample--------------')
    h3 = np.random.sample(size=(2,2))
    print(h3)
    print(h3.shape)
    print('矩阵的点乘')
    print('--------------------------')
    x = np.dot(h,h1)#矩阵的点乘，按元素进行相乘
    print(x)
    print('--------矩阵的转置--------')
    print(x.T)
    
    print('')
    print('------广播-------')
    print('矩阵的shape不一致，通过reshape进行调整')
    x = np.random.randint(2,8,size=(3,4))
    y = np.random.randint(1,9,size=(4,3))
    print('y:',y)
    y = y.reshape(3,4)
    print('x:',x)
    print('y:',y)
    print('x+y=',x+y)
    
    print('')
    print('------np.arange()------')
    a = np.arange(20,step = 2).reshape(2,5)#按排列的顺序生成start=0，end < 20，step = 2的整数，再利用reshape组成一个2*5的矩阵
    print(a)
    print('')

运行结果如下：

"D:/python project/deep learing/numpy/1.1.py"
    [2 1 4 6 3]
    =================================
    [[0. 0. 0. 0.]
     [0. 0. 0. 0.]
     [0. 0. 0. 0.]]
    =================================
    [[1. 1. 1.]
     [1. 1. 1.]
     [1. 1. 1.]
     [1. 1. 1.]]
    =================================
    [[1 2 3]
     [2 3 4]
     [3 4 5]
     [4 5 6]]
    =================================
    [[[0.07269259 0.10318425]
      [0.63483835 0.57930749]
      [0.45847482 0.96380657]]
    
     [[0.19184909 0.40354845]
      [0.71109631 0.37428877]
      [0.45283132 0.47235885]]
    
     [[0.87023493 0.21834932]
      [0.44186986 0.24913898]
      [0.87391932 0.61050419]]
    
     [[0.05497517 0.12890712]
      [0.28894985 0.51151779]
      [0.37588991 0.93231969]]]
    **********************************
    [[0.24929256 0.19597898 0.80631295 0.7228318 ]
     [0.71598807 0.10716338 0.9645689  0.0378334 ]]
    =================================
    [[[ 0.6093495  -1.35627677]
      [-0.66191887 -1.09727734]
      [ 1.29890737  0.73013595]]
    
     [[ 0.01984872 -0.5046301 ]
      [ 0.66322497 -0.18515963]
      [ 0.25616161 -0.67217041]]
    
     [[ 2.5878127  -0.23893   ]
      [-1.46914138  0.16057052]
      [-0.5969543  -2.06847457]]
    
     [[-0.13046129 -0.29135587]
      [-1.13931236 -1.69595818]
      [ 0.56978455 -0.50754035]]
    
     [[ 0.55880953  1.85532563]
      [-0.86423249  0.41589772]
      [ 0.26275627  0.57950653]]]
    **********************************
    [[-1.86412133 -0.30360421  0.88771507 -2.25272266]
     [ 1.41712964  0.47065414  0.35724498 -0.25150316]]
    =================================
    [[6 9 6 8 4 3 6 9]
     [5 4 7 2 4 5 4 2]
     [1 3 1 6 5 5 7 1]
     [6 1 5 8 6 6 3 9]
     [2 4 6 9 4 1 1 6]
     [6 9 5 3 9 8 7 6]
     [6 4 7 4 9 5 6 8]
     [4 4 4 9 5 7 3 7]
     [3 3 4 7 7 7 6 4]
     [4 6 3 3 4 9 3 1]]
    **********************************
    4
    随机生成[0，1）之间的浮点数
    -----------random_sample--------------
    [[0.70630401 0.23234587]
     [0.05806361 0.57765543]
     [0.13450884 0.74544632]]
    -----------random--------------
    [[0.36338596 0.82962207]
     [0.04111808 0.55551702]]
    -----------ranf--------------
    [[0.9477004  0.51604987]
     [0.82221483 0.40770065]]
    -----------sample--------------
    [[0.21015343 0.9623032 ]
     [0.83385894 0.15097825]]
    (2, 2)
    矩阵的点乘
    --------------------------
    [[0.26621458 0.71503748]
     [0.04485158 0.36906828]
     [0.07952995 0.52569963]]
    --------矩阵的转置--------
    [[0.26621458 0.04485158 0.07952995]
     [0.71503748 0.36906828 0.52569963]]
    
    ------广播-------
    矩阵的shape不一致，通过reshape进行调整
    y: [[8 6 7]
     [7 4 7]
     [7 4 5]
     [1 8 4]]
    x: [[6 4 7 6]
     [3 7 6 5]
     [4 5 6 3]]
    y: [[8 6 7 7]
     [4 7 7 4]
     [5 1 8 4]]
    x+y= [[14 10 14 13]
     [ 7 14 13  9]
     [ 9  6 14  7]]
    
    ------np.arange()------
    [[ 0  2  4  6  8]
     [10 12 14 16 18]]
    
    Process finished with exit code 0