On Wed, Mar 24, 2010 at 8:52 AM, mgierdal <mgier...@gmail.com> wrote:
>
> I have a dataFrame variable:
>
> L1 L2 L3 ... v1 v2 ...
> 1
> 2
> 3
> 4
> ...
>
> I want to process subsets of it as defined by combinations of L1-L2-L3. I do
> it successfully using nested loops:
>
> for (i in valuesOfL1 {
> for (j in valuesOfL2) {
> for (k in valuesOfL3) {
> tempData <- subset(dataFrame, (L1 == i & L2 == j & L3 == k,
> select=c(v1,v2) ))
> if (dim(tempData)[1]>0) # does this combination of L1-L2-L3 contain
> any data?
> { process(tempData) }
> }
> }
> }
>
> It works fine but:
> 1. I'm sure there can be more efficient solution
> 2. each time I want to change criteria (i.e. subset by less or more Ls) I
> have to manually change number of nested loops in my code.
?split
library(plyr)
?ddply
Hadley
--
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/
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