[机器学习][基础编程][numpy]numpy创建数组

男娘i 2023-05-29 06:18 20阅读 0赞

import numpy as np

a = np.array([1,2,3,4])
    b = np.array([5,6,7,8])
    print(a)
    print(b)

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

a_two = np.array([
        [1,2,3],
        [4,5,6],
        [7,8,9]
    ])
    print(a_two)

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

b_two = np.array([
        [
            [1,2,3,4],
            [5,6,7,8],
            [9,10,11,12]
        ],
        [
            [11,12,13,14],
            [15,16,17,18],
            [19,20,21,22]
        ]
    ])
    print(b_two)

[[[ 1  2  3  4]
      [ 5  6  7  8]
      [ 9 10 11 12]]
    
     [[11 12 13 14]
      [15 16 17 18]
      [19 20 21 22]]]

## Zero创建 ##

np.zeros((3,2))

array([[0., 0.],
           [0., 0.],
           [0., 0.]])

np.ones((4,2))

array([[1., 1.],
           [1., 1.],
           [1., 1.],
           [1., 1.]])

np.empty((3,2))

array([[0., 0.],
           [0., 0.],
           [0., 0.]])

## Other方式创建 ##

np.arange(20)

array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16,
           17, 18, 19])

np.arange(10,20)

array([10, 11, 12, 13, 14, 15, 16, 17, 18, 19])

np.arange(10,20,2)

array([10, 12, 14, 16, 18])

np.arange(15,10,-1)

array([15, 14, 13, 12, 11])

# 形成一个包含5个元素的数组，元素之间是等差数列变化，差值为：5
    np.linspace(0,10,5)

array([ 0. ,  2.5,  5. ,  7.5, 10. ])

# 0表示10 的零次方，2表示10的2次方，5表示最终生成的元素数量为5个（可以通过base来指定具体的底数）
    np.logspace(0,2,5)

array([  1.        ,   3.16227766,  10.        ,  31.6227766 ,
           100.        ])

np.random.random((3,2,3))

array([[[0.77613496, 0.57063526, 0.13592671],
            [0.37200255, 0.57940589, 0.04523521]],
    
           [[0.00988416, 0.0241904 , 0.03610449],
            [0.2683299 , 0.14899157, 0.24538656]],
    
           [[0.69351388, 0.01472754, 0.23379078],
            [0.06333612, 0.59183211, 0.73581303]]])