[R] Selecting elements in vector

Gabor Csardi csardi at rmki.kfki.hu
Fri Mar 14 12:00:25 CET 2008


Use %in%:

x [ x %in% y ]

G.

On Fri, Mar 14, 2008 at 12:37:45PM +0200, Rainer M Krug wrote:
> Hi
> 
> Consider the following code
> 
> > x <- rep(1:13, 13)
> 
> > y <- 1:3
> 
> I want to select all elements in x which are equal to 1, 2 or 3.
> 
> I know that I could use
> 
> > sel <- x==y[1] | x==y[2] | x==y[3]
> > x[sel]
> 
> to obtain the values, but in my analysis, the y-vector is thousands of
> elements long.
> 
> Is there any way, that I can do that easily?
> 
> Thanks
> 
> Rainer
> -- 
> Rainer M. Krug, Dipl. Phys. (Germany), MSc Conservation Biology (UCT)
> 
> Plant Conservation Unit Department of Botany
> University of Cape Town
> Rondebosch 7701
> South Africa
> 
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-- 
Csardi Gabor <csardi at rmki.kfki.hu>    UNIL DGM



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