[R] subset in a matrix

[Henrique Dallazuanna]

Try this:

z[z[,1] < 0,]

On Tue, Feb 9, 2010 at 6:12 PM, DonDiego <jorge.nieves at moorecap.com> wrote:
>
> Hi,
>
> I have a matrix of data values like the example bellow. I would like to
> extract a subset of the matrix for the values where the first column is
> negative.  I am using the subset function. However, I am getting an error
> message that the conditional variable doe snot exist.  For some reason, the
> subset operation only works if I transform the matrix to a data set using
> as.data.set(). The help indicates that the subset function can be applied to
> matrixes and data sets. I am wondering if anyone has seen a similar problem
> before. am I using the correct syntax?
>
>
>
> n = 15
> m = 5
>
> cnames = paste("x",1:m,sep="")
> rnames = 1:n
>
> z = matrix(rnorm(n*m),n,m,dimnames =list(rnames,cnames))
>
>
> Thanks,
>
> Jorge
>
>
>
>
> test = subset(z,x1 < 0, select = c(cnames))
>
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>



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