matplotlib 次坐标轴

import matplotlib.pyplot as pltimport numpy as npx = np.arange(0,10,0.1)y1 = 0.05 * x**2y2 = -1*y1fig,ax1 = plt.subplots()ax2 = ax1.twinx()ax1.plot(x,y1,'g-')ax2.plot(x,y2,'b--')ax1.set_xlabel('X data')ax1.set_ylabel('Y1',color='g')ax2.set_ylabel('Y2',color='b')plt.show()