图形中添加纯文本注释(text)

在图形中，通过text添加纯文本的注释

text所有相关的参数：官网链接

#!/usr/bin/python#coding: utf-8import numpy as npimport matplotlib.pyplot as pltx = np.arange(-10, 11, 1)y = x ** 2plt.plot(x, y)# 第一个参数是x轴坐标# 第二个参数是y轴坐标# 第三个参数是要显式的内容# alpha 设置字体的透明度# family 设置字体# size 设置字体的大小# style 设置字体的风格# wight 字体的粗细# bbox 给字体添加框，alpha 设置框体的透明度， facecolor 设置框体的颜色plt.text(-3, 20, "function: y = x * x", size = 15, alpha = 0.2)plt.text(-3, 40, "function: y = x * x", size = 15,\         family = "fantasy", color = "r", style = "italic", weight = "light",\         bbox = dict(facecolor = "r", alpha = 0.2))plt.show()