[R] How to insert a vector or matrix into an existing matrix

Gabor Csardi csardi at rmki.kfki.hu
Mon Apr 21 09:10:02 CEST 2008


On Sun, Apr 20, 2008 at 08:16:11PM +0000, David Winsemius wrote:
> Gabor Csardi <csardi at rmki.kfki.hu> wrote in
> news:20080420133926.GA28167 at localdomain: 
> 
> > Hmm, my understanding is different,
> > 
> > m <- matrix(sample(10*10), ncol=10)
> > m2 <- rbind( m[1:5,], 1:10, m[6:10,] )
> > m3 <- cbind( m[,1:8], 1:10, m[,9:10] )
> 
> I read the question the same way and, in response to the part of the 
> question asking for no temporary matrix, offer this refinement on your 
> suggestion:
> 
> m <- rbind(  m[1:5,], 1:10, m[6:10,] ) # row insertion or ...
> 
> # not to be followed by, but rather instead column insertion ..
> m <- cbind( m[,1:8], 1:10, m[,9:10] )

There might be something wrong with my eyes, but where is the refinement
here? Your lines are literally the same as mines. There is no temporary 
matrix here, m2 and m3 are the results, he wanted either between row 
5 and 6 _OR_ column 8 and 9. 

Oh, if you mean that we immediately put back the result into 'm',
then 1) it does not really matter, R will create a temporary matrix 
internally anyway, 2) i assumed that the user can figure this 
out him/herself.

G.

> -- 
> David Winsemius
> 
> > 
> > G.
> > 
> > On Sun, Apr 20, 2008 at 10:21:47AM -0300, Henrique Dallazuanna
> > wrote: 
> >> If I understand:
> >> 
> > 
> >> m <- matrix(sample(10*10), ncol=10)
> >> m[5:6, 8:9] <- 1:4
> >> 
> > 
> >> 
> > 
> >> 
> > 
> >> On 4/18/08, Ng Stanley <stanleyngkl at gmail.com> wrote:
> >> > Hi,
> >> >
> >> > Is there any functions to insert a vector or matrix into an
> >> > existing ma 
> > trix
> >> > say between row 5 and 6 or column 8 and 9, without creating a
> >> > temporary matrix ?
> >> >
> >> > Thanks
> >> > Stanley
> 
> ______________________________________________
> 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.

-- 
Csardi Gabor <csardi at rmki.kfki.hu>    UNIL DGM



More information about the R-help mailing list