python code for lagrange interpolation

lagint.py

import numpy as np
import matplotlib.pyplot as plt


rawData = np.loadtxt("inputData.dat")
x = rawData.transpose()[0]
y = rawData.transpose()[1]

xnew = np.loadtxt("x.dat")
ynew = np.zeros(len(xnew))

for k in range(len(xnew)):
	suum1 = 0
	for i in range(len(x)):
		y1 =1
		for j in range(len(x)):
			if i != j:
				y1 *= (xnew[k] - x[j]) / (x[i] - x[j])
				
		suum1 += y[i] * y1
	ynew[k] = suum1
np.savetxt("lagint.dat",np.c_[xnew,ynew],fmt = "%10.3e")
plt.plot(x,y,"r")
plt.plot(xnew, ynew, "bo")
plt.show()