[R] Rbind help needed

John Fox jfox at mcmaster.ca
Wed Nov 27 21:29:43 CET 2002

At 01:23 PM 11/27/2002 -0500, Bayesianbay at aol.com wrote:

>I have a very simple question which is causing me problems!
>I have a matrix A and simply want to rbind this matrix together n times (n 
>is a large number)
>How can I write this in R?
>I know I could do new<-rbind(z,z,z,...z) with z written n times but this 
>will take forever as n is so large.
>Is there a simple way to write this?

Dear Mick,

If efficiency isn't an issue, you could do

B <- A
for (i in 1:(n - 1)) B <- rbind(B, A)

A more efficient, but less transparent, approach would be

matrix(rep(t(A), n), nrow(A)*n, ncol(A), byrow=TRUE)

I hope that this helps,

John Fox
Department of Sociology
McMaster University
email: jfox at mcmaster.ca
web: http://www.socsci.mcmaster.ca/jfox

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