01-numpy基础简介

 1 import numpy as np
 2 
 3 # ndarray
 4 
 5 ‘‘‘
 6     # 三种创建方式
 7     1、从python的基础数据对象转化
 8     2、通过numpy内置的函数生成
 9     3、从硬盘（文件）读取数据
10 ‘‘‘
11 # 创建方法一
12 a= [1,2,3,4]
13 x1 = np.array(a)
14 print(x1,"\n",type(x1))
15 
16 # 创建方法二
17 x = np.arange(5)
18 print(x,"\n",type(x))
19 
20 # # 创建方法三
21 # date,Open,low = np.loadtxt(‘..csv‘,delimiter="\t",skiprows=1,usecols=(1,2,4),unpack=True)
22 # print(date,"\n",Open,"\n",low)
23 
24 
25 # 常用函数
26 ‘‘‘
27     min     最小值
28     max     最大值
29     median      中值
30     mean        均值
31     variance        方差
32     sort        
33 ‘‘‘
34 
35 c = np.random.randint(1,100,10)
36 print(np.sort(c))
37 print(np.mean(c))
38 
39 
40 # 练习
41 ‘‘‘
42     使用numpy生成100以内的随机数组
43     将数组存储到文件，再从文件中读取数组
44     对数据进行sort ,max ,min ,mean ,variance
45 ‘‘‘
46 
47 N1 = np.random.randint(0,100,10)
48 # 将N1 存储到文件中
49 np.savetxt("0002.cvs",N1,fmt = "%d",delimiter=",",header="number")
50 # 从文件中读取数组
51 N2 = np.loadtxt("0002.cvs",delimiter=",",skiprows=1)
52 
53 print(np.sort(N2))
54 print(np.max(N2))