#-*- coding:utf-8 -*-import mathimport matplotlib.pyplot as pltdef linefit(x , y):  N = float(len(x))  sx,sy,sxx,syy,sxy=0,0,0,0,0  for i in range(0,int(N)):    sx += x[i]    sy += y[i]    sxx += x[i]*x[i]    syy += y[i]*y[i]    sxy += x[i]*y[i]  a = (sy*sx/N -sxy)/( sx*sx/N -sxx)  b = (sy - a*sx)/N  r = abs(sy*sx/N-sxy)/math.sqrt((sxx-sx*sx/N)*(syy-sy*sy/N))  return a,b,rif __name__ == '__main__':  x=[ 1 ,2 ,3 ,4 ,5 ,6]  y=[ 2.5 ,3.51 ,4.45 ,5.52 ,6.47 ,7.51]  a,b,r=linefit(x,y)  print("X=",x)  print("Y=",y)  print("擬合結果: y = %10.5f x + %10.5f , r=%10.5f" % (a,b,r) )  plt.plot(x, y, "r:", linewidth=2)  plt.grid(True)  plt.show()

#-*- coding:utf-8 -*-import numpy as npimport matplotlib.pyplot as pltimport mathf = lambda x:5*x+4tx = np.linspace(0,10,50)print txplt.plot(tx, f(tx), "r-", linewidth=2)plt.grid(True)plt.show()