# Re: [R] intersecting rows of a matrix

From: Henrique Dallazuanna <wwwhsd_at_gmail.com>
Date: Wed, 20 Feb 2008 21:47:44 -0300

lk.list<-split(lk.mat.test,1:nrow(lk.mat.test)) names(lk.list)<-NULL
do.call(intersection,lk.list)

2008/2/20, dxc13 <dxc13_at_health.state.ny.us>:
>
> useR's,
>
> First, I would like to say thanks to John Fox for providing this segment of
> code to perform intersection for multiple sets:
> intersection <- function(x, y, ...){
> if (missing(...)) intersect(x, y)
> else intersect(x, intersection(y, ...))
> }
>
> I want to execute this function on the rows of a matrix I have:
> Ik.mat.test <- matrix(c(2,3,6,1,2,6,6,1,2),byrow=T,nrow=3)
> > Ik.mat.test
> [,1] [,2] [,3]
> [1,] 2 3 6
> [2,] 1 2 6
> [3,] 6 1 2
>
> I need to find a way to run the intersection function on the rows of this
> matrix. The result should be a vector containing 2, 6.
> This works, but I want to find a way to do this for any size matrix.
> intersection(Ik.mat.test[1,],Ik.mat.test[2,], Ik.mat.test[3,])
> So, if the user supplied a matrix with any number of rows, I would like to
> be able to run this function. Any ideas?
> I have tried something like
> do.call(intersection, list(Ik.mat.test[1,]: Ik.mat.test[3,]))
> but this doesnt work
>
> Derek
>
>
>
> --
> View this message in context:
> http://www.nabble.com/intersecting-rows-of-a-matrix-tp15601658p15601658.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help_at_r-project.org mailing list
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> and provide commented, minimal, self-contained, reproducible code.
>

```--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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