[R] How to get row numbers of a subset of rows

[affy snp]

Thank you very much, Julian. I got it.

Best,
    Allen

On Nov 14, 2007 2:38 PM, Julian Burgos <jmburgos at u.washington.edu> wrote:
> One way to do this is
>
> range(which(B[,2]==1))
>
> Julian
>
>
> affy snp wrote:
> > Hello list,
> >
> > I read in a txt file using
> >
> > <B<-read.table(file="data.snp",header=TRUE,row.names=NULL)
> >
> > by specifying the row.names=NULL so that the rows are numbered.
> > Below is an example after how the table looks like using
> > <B[1:10,1:3]
> >
> >
> >       SNP                Chromosome  PhysicalPosition
> > 1 SNP_A-1909444          1           7924293
> > 2 SNP_A-2237149          1           8173763
> > 3 SNP_A-4303947          1           8191853
> > 4 SNP_A-2236359          1           8323433
> > 5 SNP_A-2205441          1           8393263
> > 6 SNP_A-1909445          1           7924293
> > 7 SNP_A-2237146          2           8173763
> > 8 SNP_A-4303946          2           8191853
> > 9 SNP_A-2236357          2           8323433
> > 10 SNP_A-2205442         2           8393263
> >
> > I am wondering if there is a way to return the start and end row numbers
> > for a subset of rows.
> >
> > For example, If I specify B[,2]=1, I would like to get
> > start=1 and end=6
> >
> > if B[,2]=2, then start=7 and end=10
> >
> > Is there any way in R to quickly do this?
> >
> > Thanks a bunch!
> >
> > Allen
> >
>
> > ______________________________________________
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> > and provide commented, minimal, self-contained, reproducible code.
>
>