matplotlib同一张图拟合两条曲线

import matplotlib.pyplot as plt  
  
migtime = [16.6,16.5,16.9,17.1,17.2,18.1,18.2,18.4,19.4,19.3,20.4,20.3,22,21.7,22]  
delay = [108,98,92,83,87,77,85,48,31,58,35,43,36,31,19]  
   
  
plt.xlabel('migration speed (MB/s)')  
plt.ylabel('migration time (s); request delay (ms)')  
  
"""set interval for y label"""  
yticks = range(10,110,10)  
ax.set_yticks(yticks)  
  
  
"""set min and max value for axes"""  
ax.set_ylim([10,110])  
ax.set_xlim([58,42])  
  
  
x = [57,56,55,54,53,52,51,50,49,48,47,46,45,44,43]  
plt.plot(x,migtime,"x-",label="migration time")  
plt.plot(x,delay,"+-",label="request delay")  
  
"""open the grid"""  
plt.grid(True)  
  
plt.legend(bbox_to_anchor=(1.0, 1), loc=1, borderaxespad=0.)  
  
plt.show()