画箭头提示信息

# -*- coding:utf-8 -*-
import matplotlib.pyplot as plt
import numpy as np

# 画提示信息

x = np.arange(-10,11,1)

y = x*x
plt.plot(x,y)
plt.annotate('this is hint',xy=(0,1),xytext=(0,20),arrowprops=dict(facecolor='r',frac=2,headwidth=20,width=10))
plt.show()