Create triangular matrix from vector

I have a vector, v = [x1, x2, x3 ....,xn]

I want to create a matrix from it in two ways: Upper triangular

x1 x2 x3.... xn

0 x2 x3 .... xn

0 0 x3 .....xn

. . . . . . ...

0 0 0 . . . . xn

Next, lower triangular:

x1 0 0 . .. 0

x1 x2 0 .... 0

. . . . .

x1 x2 .........xn

How can I do it without loops and conditional statements ?

Thank you.

[Scott MacKenzie]

This looks like a homework question. Have you tried any possible solutions? Please post what you have tried and ask a specific question about what you don't understand.

[Sib RV]

It is already answered here. https://www.mathworks.com/matlabcentral/answers/114517-transforming-vector-into-triangular-matrix?s_tid=answers_rc1-1_p1_MLT

Answer 1

[KSSV]

REad about triu and tril.