numpy.polyval() in Python

numpy.polyval(p, x) method evaluates a polynomial at specific values.

If ‘N’ is the length of polynomial ‘p’, then this function returns the value

Parameters :
p : [array_like or poly1D] polynomial coefficients are given in decreasing order of powers. If the second parameter (root) is set to True then array values are the roots of the polynomial equation.
For example : poly1d(3, 2, 6) = 3x² + 2x + 6

x : [array_like or poly1D] A number, an array of numbers, for evaluating ‘p’.

Return: Evaluated value of polynomial.

Code : Python code explaining polyval()

# Python code explaining
# numpy.polyval()

# importing libraries
import numpy as np
import pandas as pd

# Constructing polynomial
p1 = np.poly1d([1, 2])
p2 = np.poly1d([4, 9, 5, 4])

print ("P1 : ", p1)
print ("\n p2 : \n", p2)

# Solve for x = 2
print ("\n\np1 at x = 2 : ", p1(2))
print ("p2 at x = 2 : ", p2(2))

a = np.polyval([1, 2], 2)
b = np.polyval([4, 9, 5, 4], 2)

print ("\n\nUsing polyval")
print ("p1 at x = 2 : ", a)
print ("p2 at x = 2 : ", b)

c = np.polyval(np.poly1d([4, 9, 5, 4]), np.poly1d(2))
print ("\nc : ", c)