# numpy.polyval() in Python

• Last Updated : 29 Nov, 2018

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)`

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