[R] Rbind help needed
Tony Plate
tplate at blackmesacapital.com
Wed Nov 27 21:10:42 CET 2002
At 01:23 PM 11/27/2002 -0500, Bayesianbay at aol.com wrote:
>Dear list
>
>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?
An easy way is to not use rbind, but to use row-indexing, e.g.:
> x <- matrix(1:4, ncol=2)
> x
[,1] [,2]
[1,] 1 3
[2,] 2 4
> rep(seq(len=nrow(x)),3)
[1] 1 2 1 2 1 2
> x[rep(seq(len=nrow(x)),3),]
[,1] [,2]
[1,] 1 3
[2,] 2 4
[3,] 1 3
[4,] 2 4
[5,] 1 3
[6,] 2 4
>
-- Tony Plate
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