[R] Creating a Matrix from a vector with some conditions
Petr Savicky
savicky at cs.cas.cz
Sat Jan 8 23:52:23 CET 2011
On Thu, Jan 06, 2011 at 01:34:31PM -0800, ADias wrote:
>
> Hi
>
> Suppose we have an object with strings:
>
> A<-c("a","b","c","d")
>
> Now I do:
>
> B<-matrix(A,4,4, byrow=F)
>
> and I get
>
> a a a a
> b b b b
> c c c c
> d d d d
>
> But what I really want is:
>
> a b c d
> b c d a
> c d a b
> d a b c
>
> How can I do this?
Try the following
v <- rep(c("a", "b", "c", "d"), times=2)
a <- matrix(nrow=4, ncol=4)
a[, ] <- v[row(a) + col(a) - 1]
a
[,1] [,2] [,3] [,4]
[1,] "a" "b" "c" "d"
[2,] "b" "c" "d" "a"
[3,] "c" "d" "a" "b"
[4,] "d" "a" "b" "c"
Petr Savicky.
More information about the R-help
mailing list