matplotlib18:注释

import matplotlib.pyplot as plt
import numpy as np
x = np.arange(-10,11,1)
y = x*x
plt.plot(x,y)
plt.annotate('shis is the bootm',
             xy=(0,1),xytext=(0,20),
             arrowprops=dict(facecolor='r',
                             frac=0.2,
                             headwidth=30
                             ,width=10))


plt.show()