库的基本使用

1.Numpy-科学计算库

import numpy
i = numpy.array([[520,13,14],[25,9,178]])
print("i:\n{}".format(i))

2.Scipy-强大的科学计算工具集

import numpy as np   #取别名np
from scipy import sparse
 
matrix = np.eye(6)  #eye函数生成6*6矩阵，其中对角线为1
sparse_matrix = sparse.csr_matrix(matrix) #吧np数值转换成csr格式的scipy稀疏矩阵（只会存取非0的元素）
print("对角矩阵：\n{}".format(matrix))
print("稀疏矩阵: \n{}".format(sparse_matrix))

3.pandas-数据分析的利器

import pandas
import numpy as np
import matplotlib.pyplot as plt
 
data ={"Name":["小米","小红","小面","小张"],
      "City":["北京","上海","广州","深圳"],
      "Age":["28","29","26","30"]}
 
data_frame = pandas.DataFrame(data)
display(data_frame)
 
display(data_frame[data_frame.City!="北京"])
 
x = np.linspace(-20,20,10)
y = x**3 + 2*x**2 + 6*x +5
 
plt.plot(x,y,marker = "o")
plt.show()