# -*- coding: utf-8 -*-
#! python2
import numpy as np 
import matplotlib.pyplot as plt 
from pylab import mpl
mpl.rcParams['font.sans-serif'] = ['SimHei'] # 指定默认字体
plt.rcParams['axes.unicode_minus']=False    #解决负数坐标显示问题 
#x的个数决定了样本量
x = np.arange(-1,1,0.02) 
#y为理想函数 
y = 2*np.sin(x*2.3)+0.5*x**3
#y1为离散的拟合数据
y1 = y+0.5*(np.random.rand(len(x))-0.5)
z1 = np.polyfit(x, y, 6)
# 生成多项式对象
p1 = np.poly1d(z1)
pp1=p1(x)
##################################
#plt.plot(x,y,color='g',linestyle='-',marker='',label=u'理想曲线') 
plt.plot(x,y1,color='m',linestyle='',marker='o',label=u'拟合数据')
plt.plot(x,pp1,color='b',linestyle='-',marker='.',label=u"拟合曲线") 
# 把拟合的曲线在这里画出来
plt.legend(loc='upper left')
plt.show()

from pylab import mpl
mpl.rcParams['font.sans-serif'] = ['SimHei'] # 指定默认字体

plt.rcParams['axes.unicode_minus']=False