[R] identify subsets based on two grouping factors

[Phil Spector]

Rajarshi -
    It's not clear to me what you mean by "the distribution of 
levels obs.".  Does

as.data.frame(table(x$obs,cut.grp1,cut.grp2))

give you something like what you want?

 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu


On Mon, 31 Jan 2011, Rajarshi Guha wrote:

> Hi, I have a data.frame that has a categorical variable, for which I
> would like to look at the distribution of levels of this variable,
> based on a grouping of two other variables.
>
> As an example:
>
> x <- data.frame(obs=sample(c('low', 'high'),100, replace=TRUE),
> grp1=sample(1:10, 100, replace=TRUE),
> grp2=runif(100))
>
> cut.grp1 <- cut(x$grp1, 3)
> cut.grp2 <- cut(x$grp2, 3)
>
> Thus, for each combination of levels in cut.grp1 and cut.grp2, I'd
> like to obtain the distribution of levels obs. I know I can loop over
> each pair of levels in cut.grp1 and cut.grp2, but is there a more
> elegant way to achieve this?
>
> -- 
> Rajarshi Guha
> NIH Chemical Genomics Center
>
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