Create lower triangular matrix from a vector in python

Question

I want to create a python program which computes a matrix from a vector with some coefficients. So lets say we have the following vector of coefficients c = [c0, c1, c2] = [0, 1, 0], then I want to compute the matrix:

So how do I go from the vector c to creating a lower triangular matrix A. I know how to index it manually, but I need a program that can do it. I was maybe thinking about a for-loop inside another for-loop but I struggle with how it is done practically, what do you guys think should be done here?

Answer 1

One way (assuming you're using plain arrays and not numpy or anything):

src = [0, 1, 0]
dst = [
    [ 
        src[i-j] if i >= j else 0
        for j in range(len(src))
    ] for i in range(len(src))
]