python使用Matplotlib绘制分段函数

# coding:utf-8 """Author: roguesirDate: 2017/8/30GitHub: https://roguesir.github.comBlog: http://blog.csdn.net/roguesir""" import numpy as npimport matplotlib.pyplot as plt def sgn(value): if value < 4: return 20 else: return 15plt.figure(figsize=(6,4))x = np.linspace(0, 8, 100)y = np.array([])for v in x: y = np.append(y,np.linspace(sgn(v),sgn(v),1))l=plt.plot(x,y,'b',label='type')plt.legend()plt.show()