#### Diagonal Arrays

The

**diag(V, k=0)**

function allows you to extract a diagonal from an array, as well as build diagonal arrays from one-dimensional arrays.

`V`

- An array-like object, two-dimensional or one-dimensional arrays, matrices, lists, or tuples, or any function or object with a method that returns a list or tuple.

k - index of the diagonal (optional).

The default is

`k = 0`

which corresponds to the main diagonal. A positive

`k`

value moves the diagonal up, a negative value moves it down.

The function returns array

`NumPy `(

`ndarray`

) - the specified array diagonal or a diagonal array from the specified one-dimensional array.