matplotlib plotting sine and cosine curves

an introduction

Keywords: drawing library

Official website: http://matplotlib.org

two code

1. import numpy as np
2. import matplotlib.pyplot as plt
3. #line
4. x=np.linspace(-np.pi,np.pi,256,endpoint=True)
5. #定义余弦函数正弦函数
6. c,s=np.cos(x),np.sin(x)
7. plt.figure(1)
8. #画图，以x为横坐标，以c为纵坐标
9. plt.plot(x,c,color="blue",linestyle="-",label="COS",alpha=0.5)
10. plt.plot(x,s,"r*",label="SIN")
11. #增加标题
12. plt.title("COS & SIN")
13. ax=plt.gca()
14. ax.spines["right"].set_color("none")
15. ax.spines["top"].set_color("none")
16. ax.spines["left"].set_position(("data",0))
17. ax.spines["bottom"].set_position(("data",0))
18. ax.xaxis.set_ticks_position("bottom")
19. ax.yaxis.set_ticks_position("left")
20. plt.xticks([-np.pi,-np.pi/2,0,np.pi/2,np.pi],
21. [r'$-\pi$',r'$-\pi/2$',r'$0$',r'$+\pi/2$',r'$+\pi$'])
22. plt.yticks(np.linspace(-1,1,5,endpoint=True))
23. for label in ax.get_xticklabels()+ax.get_yticklabels():
24. label.set_fontsize(16)
25. label.set_bbox(dict(facecolor="white",edgecolor="None",alpha=0.2))
26. #图例显示
27. plt.legend(loc="upper left")
28. #显示网格
29. plt.grid()
30. #显示范围
31. #plt.axis([-1,1,-0.5,1])
32. plt.fill_between(x,np.abs(x)<0.5,c,c>0.5,color="green",alpha=0.25)
33. t=1
34. plt.plot([t,t],[0,np.cos(t)],"y",linewidth=3,linestyle="--")
35. plt.annotate("cos(1)",xy=(t,np.cos(1)),xycoords="data",xytext=(+10,+30),
36. textcoords="offset points",arrowprops=dict(arrowstyle="->",connectionstyle="arc3,rad=.2"))
37. #显示图形
38. plt.show()

Three running results