`numpy.ma.extras:diagflat`

Signature

def diagflat(v, k = 0)

Create a two-dimensional array with the flattened input as a diagonal.

v : array_like: Input data, which is flattened and set as the k-th diagonal of the output.
k : int, optional: Diagonal to set; 0, the default, corresponds to the "main" diagonal, a positive (negative) k giving the number of the diagonal above (below) the main.

The function is applied to both the _data and the _mask, if any.

import numpy as np
np.diagflat([[1,2], [3,4]])

✓

array([[1, 0, 0, 0],
       [0, 2, 0, 0],
       [0, 0, 3, 0],
       [0, 0, 0, 4]])

np.diagflat([1,2], 1)

✓

array([[0, 1, 0],
       [0, 0, 2],
       [0, 0, 0]])