[R] expand the inside of command with rep ?

[Petr PIKAL]

Hi



r-help-bounces at r-project.org napsal dne 10.02.2010 21:32:29:

> try this:
> 
> > x <- 1:5
> > x.list <- lapply(1:15, function(a) x)
> > do.call(cbind, x.list)
>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> [,13] [,14] [,15]
> [1,]    1    1    1    1    1    1    1    1    1     1     1     1
>  1     1     1
> [2,]    2    2    2    2    2    2    2    2    2     2     2     2
>  2     2     2
> [3,]    3    3    3    3    3    3    3    3    3     3     3     3
>  3     3     3
> [4,]    4    4    4    4    4    4    4    4    4     4     4     4
>  4     4     4
> [5,]    5    5    5    5    5    5    5    5    5     5     5     5
>  5     5     5
> >

Another option is

n=15
matrix(rep(x, each=n), nrow=length(x), ncol=n)

Regards
Petr


> 
> 
> On Wed, Feb 10, 2010 at 3:27 PM, Xu Wang <xuwang762 at gmail.com> wrote:
> >
> > Hi,
> >
> > I would like to be able to repeat a string within a command. I think 
there
> > is an easy way but I can not figure out how.
> >
> > Here is an example.
> >
> > x<-1:15
> > I would like to turn this into the following matrix:
> > xm<-cbind(x,x,x,x,x)
> >
> > But I would like to do so by having a command that repeats x within 
the
> > cbind command. Does that make sense? I have tried various things 
mainly
> > involving the commands "rep" and "paste" but cannot get it.
> >
> > cbind(rep('x',times=5))
> >
> > I am guessing that this is not good programming etiquette? Something 
seems
> > off about it. But still, I would like to know how to do it.
> >
> > I do understand that I can use a for loop to easily accomplish the 
desired
> > output but am looking for a solution similar to the above syntax.
> >
> > Thank you for any ideas,
> >
> > Xu Wang
> > --
> > View this message in context: 
http://n4.nabble.com/expand-the-inside-of-
> command-with-rep-tp1476420p1476420.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.
> >
> 
> 
> 
> -- 
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
> 
> What is the problem that you are trying to solve?
> 
> ______________________________________________
> 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.