I want to make the below matrix in r:
1 0 0 4
0 2 0 5
0 0 3 6
I used the below code:
matrix(c(1,0,0,0,2,0,0,0,3,4,5,6),nrow=3)
My code works. But I do not like my solution way. I am thinking to find the simplest way for making this matrix. Do you think my code is the simplest code for making this matrix? If not, could anyone writes a simpler code than my one?
Your first matrix
> cbind(diag(1:3), 4:6)
[,1] [,2] [,3] [,4]
[1,] 1 0 0 4
[2,] 0 2 0 5
[3,] 0 0 3 6
Your second one
> matrix(1, nrow=3, ncol=3) - diag(1, 3)
[,1] [,2] [,3]
[1,] 0 1 1
[2,] 1 0 1
[3,] 1 1 0
Your third
> matrix(seq(1, 35, 2), nrow=3, byrow=TRUE)
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 1 3 5 7 9 11
[2,] 13 15 17 19 21 23
[3,] 25 27 29 31 33 35
and your final
> matrix(0.5, nrow=3, ncol=3) + diag(0.5, 3)
[,1] [,2] [,3]
[1,] 1.0 0.5 0.5
[2,] 0.5 1.0 0.5
[3,] 0.5 0.5 1.0
As @jay.sf pointed out, there is a more sophisticated solution for the second and fourth matrix:
# second matrix
`diag<-`(matrix(1, 3, 3), 0)
# fourth matrix
`diag<-`(matrix(0.5, 3, 3), 1)