题来源
https://github.com/nndl/exercise/blob/master/warmup/numpy_%20tutorial.ipynb
1.引入numpy库
from numpy import *
2.import numpy as np
x =[4,5,6]
a = np.asarray(x, dtype=int)
print (a)
print (a.shape)
print (a.dtype.name)
print (a[0])
3import numpy as np
x =[[4,5,6],[1,2,3]]
b = np.asarray(x, dtype=int)
print (b.shape)
print (b[0][0])
print (b[0][1])
print (b[1][1])
4
import numpy as np
a = np.zeros((3,3),dtype=int)
print(a)
print ("------------")
b = np.ones((4,5),dtype=int)
print(b)
print ("-----------")
c =np.eye(4,dtype=int)
print (c)
print ("------------")
d = np.empty([3,2], dtype = int)
print (d)
5
import numpy as np
x =[[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
a = np.asarray(x, dtype=int)
print (a)
print (a[2][3])
print (a[0][0])
6
import numpyas np
x =[[1,2,3,4], [5,6,7,8], [9,10,11,12]]
a = np.asarray(x,dtype=int)
b=np.asarray(a[[0,1]])
b=b[:,[1,2]]
print(b)
print(b[0,0])
7.
x =[[1,2,3,4], [5,6,7,8], [9,10,11,12]]
a = np.asarray(x,dtype=int)
b=np.asarray(a[[0,1]])
b=b[:,[1,2]]
c=a[1:2][:]
print (c)
print (c[0][-1])
8.
x =[[1,2], [3,4], [5,6]]
a = np.asarray(x,dtype=int)
print(a[[0,1,2], [0,1,0]])
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(1)
(2)
附加：
INF表示“无穷大”,是infinite的缩写。NAN表示“无效数字”,是Not a number的缩写。
问题：
import matplotlib.pyplot出现readtimeout
在file》》setting》》projetct interpreter》》+》》manage repositories把网址修改为下面的和里面不同的另一项
https://pypi.douban.com/simple
https://pypi.python.org/simple
不显示图
如图取消勾选
