R help - Jan 2011 - Creating a Matrix from a vector with some conditions

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?

thank you

A. Dias
-- 
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Sent from the R help mailing list archive at Nabble.com.

On Jan 6, 2011, at 4:34 PM, 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?
How else?
B<-matrix(A,4,4, byrow=TRUE)
>
> thank you
>
> A. Dias
> -- 
> View this message in context:
http://r.789695.n4.nabble.com/Creating-a-Matrix-from-a-vector-with-some-conditions-tp3178219p3178219.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT

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

  A <- c("a","b","c","d")
  B <- matrix(A, 5, 4)[1:4, ]

  #     [,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.

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.

Hi,

embed() seemed well-suited, but I couldn't figure out an elegant way to use
it

embed(c(A,A), 4)[1:4, 4:1]

HTH,

baptiste

On 6 January 2011 22:34, ADias <diasandre at gmail.com>
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?
>
> thank you
>
> A. Dias
> --
> View this message in context:
http://r.789695.n4.nabble.com/Creating-a-Matrix-from-a-vector-with-some-conditions-tp3178219p3178219.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>