# Python | Numpy np.lagvander() method

With the help of `np.lagvander()` method, we can get the Pseudo-Vandermonde matrix from given array having degree which is passed as parameter by using `np.lagvander()` method.

Syntax : `np.lagvander(arr, degree)`
Parameters:
arr :[ array_like ] Array of points. The dtype is converted to float64 or complex128 depending on whether any of the elements are complex. If x is scalar it is converted to a 1-D array
deg :[int] Degree of the resulting matrix.

Return : Return the matrix having size i.e array.size + (degree + 1).

Example #1 :
In this example we can see that by using `np.lagvander()` method, we are able to get the pseudo-vandermonde matrix using this method.

 `# import numpy ` `import` `numpy as np ` `import` `numpy.polynomial.laguerre as geek ` ` `  `# using np.lagvander() method ` `gfg ``=` `geek.lagvander((``1``, ``3``, ``5``, ``7``), ``2``) ` ` `  `print``(gfg) `

Output :

[[ 1. 0. -0.5]
[ 1. -2. -0.5]
[ 1. -4. 3.5]
[ 1. -6. 11.5]]

Example #2 :

 `# import numpy ` `import` `numpy as np ` `import` `numpy.polynomial.laguerre as geek ` ` `  `# using np.lagvander() method ` `gfg ``=` `geek.lagvander((``2``, ``5``, ``1``, ``12``), ``5``) ` ` `  `print``(gfg) `

Output :

[[ 1. -1. -1. -0.33333333 0.33333333
0.73333333]
[ 1. -4. 3.5 2.66666667 -1.29166667
-3.16666667]
[ 1. 0. -0.5 -0.66666667 -0.625
-0.46666667]
[ 1. -11. 49. -107. 97. 27.4 ]]

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