matplot.legend

import numpy as np
import matplotlib
matplotlib.use(“TkAgg”)
import matplotlib.pyplot as plt
from matplotlib.collections import LineCollection

x=np.linspace(-1,1,50)
y1=3*x+1
y2=x**2
l1,=plt.plot(x,y2,color=“g”)#注意：加逗号
l2,=plt.plot(x,y1,linewidth=1.0,linestyle=’–’,color=‘r’)注意：加逗号

plt.legend(handles=[l1,l2],labels=[“aaa”,“bbb”],loc=“best”)
matplot.legend
l1,=plt.plot(x,y2,color=“g”,label=“up”)
l2,=plt.plot(x,y1,linewidth=1.0,linestyle=’–’,color=‘r’,label=“down”)