[R] How to replace all non-maximum values in a row with 0

[Owe Jessen]

Am 09.04.2010 10:04, schrieb burgundy:
> Hi,
>
> I would like to replace all the max values per row with "1" and all other
> values with "0". If there are two max values, then "0" for both. Example:
>
> from:
> 2  3  0  0  200
> 30 0  0  2  50
> 0  0  3  0  0
> 0  0  8  8  0
>
> to:
> 0  0  0  0  1
> 0  0  0  0  1
> 0  0  1  0  0
> 0  0  0  0  0
>
> Thanks!
>    
Nice little homework to get the day started. :-)

This worked for me, but is probably not the shortest possible answer

A <- matrix (c(2,  3,  0,  0,  200, 30, 0,  0,  2,  50, 0,  0,  3,  0,  
0, 0,  0,  8,  8,  0), nrow = 4, byrow=T)
nr <- nrow(A)
nc <- ncol(A)
B <- matrix(0,nrow=nr, ncol=nc)
for(i in 1:nr){
x <- which(A[i,]==max(A[i,]))
B[i,x] <- 1
if(sum(B[i,])>1) B[i,] <- as.vector(rep(0,nc))
}

-- 
Owe Jessen
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24105 Kiel
post at owejessen.de
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