motplotlib使用

一

# -*- coding: utf-8 -*-
"""
Spyder Editor
  
This is a temporary script file.
 """

import numpy as np               #引用numpy库，从新命名它为np（以后用np代替numpy，简洁）
import matplotlib.pyplot as plt
import matplotlib
x = np.linspace(0,6,100)    #在【0，6】平均分为100个
print(x)   #输出查看一下x内容
y = np.cos(2*np.pi*x) * np.exp(-x) + 0.8   #调用np库里的cos函数
print(y)  #输出Y查看一下内容
plt.plot(x,y,'k',color='r',linewidth=3,linestyle="-") #color='r'代表红色
plt.show() #展示绘图

二

# -*- coding: utf-8 -*-
"""
Spyder Editor

This is a temporary script file.
"""

import numpy as np
import matplotlib.pyplot as plt
x=np.linspace(0,10,1000)
y=np.cos(2*np.pi*x)*np.exp(-x)+0.8
plt.plot(x,y,'k',color='r',label="$exp-decay$",linewidth=3)
plt.axis([0,6,0,1.8])
ix=(x>0.8)&(x<3)
plt.fill_between(x,y,0,where=ix,facecolor='red',alpha=0.25)
plt.text(0.5*(0.8+3),0.2,r"$int_a^b f(x)mathrm{d}x$",horizontalignment='center')
plt.legend()
plt.show()