annotation 标注

1. import matplotlib.pyplot as plt
   import numpy as np
   x=np.linspace(-3,3,50)
   y=2*x+1
   plt.figure(num=1,figsize=(8,5))
   plt.plot(x,y)
   ax=plt.gca()
   ax.spines[‘right’].set_color(‘none’)
   ax.spines[‘top’].set_color(‘none’)
   ax.spines[‘top’].set_color(‘none’)
   ax.xaxis.set_ticks_position(‘bottom’)
   ax.spines[‘bottom’].set_position((‘data’,0))
   ax.yaxis.set_ticks_position(‘left’)
   ax.spines[‘left’].set_position((‘data’,0))
   #
2. 列表内容

method 1
x0=1
y0=2*x0+1
plt.scatter(x0,y0,s=50,color=’b’)#展示一个点
plt.plot([x0,x0],[y0,0],’k–’,lw=2.0)#虚线,线的颜色和宽度
plt.annotate(r’2x+1=$2x+1=$’%y0,xy=(x0,y0),xycoords=’data’,xytext=(+30,-30),textcoords=’offset points’,fontsize=16,
arrowprops=dict(arrowstyle=’->’,connectionstyle=’arc3,rad=0.2’))

method 2

plt.text(-3.7,3,r’This is the some textσiαt$Thisisthesometext{\sigma }_i{\alpha }_t$’,
fontdict={‘size’:16,’color’:’r’})
plt.show()