[R] which() over a matrix

Chuck Cleland ccleland at optonline.net
Thu Nov 23 13:37:46 CET 2006


javier garcia-pintado wrote:
> Hello,
> A brief question that I am not able to resolve by my own, but I presume
> it's easy for you:
> 
> I've used apply to find the values closer to 0 in each row of a matrix:
> 
> closer.to.0 <- apply(abs(myarray),MARGIN=1,"min")
> 
> My question is how could I use which (or another way) to obtain a vector
> that indicates which columns contains these "closer to 0" values?

?which.min

which.closer.to.0 <- apply(abs(myarray), 1, which.min)

> (I know I can loop, but I mean a faster and elegant way)
> 
> Thanks and best regards
> 
> Javier
> 
> 
> 
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> 
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