This is a problem much like the one I had a few weeks ago. David's solution
is more concise. Try xtfrm() or rank() for factor sorting

d=data[order(data$ID,-xtfrm(data$Type)),] should work. By the way I got it
from Duncan.

Jun

On Fri, May 8, 2009 at 4:09 PM, David Freedman <3.14david@gmail.com> wrote:

>
> sorry about the mistake - the -data$Type doesn't work: the '-' sign isn't
> valid for factors.  I *thought* I had checked this before submitting a
> response !
>
>
> HufferD wrote:
> >
> > On Thursday, May 07, 2009 7:45 PM, David Freedman wrote:
> >
> >  > ...how about:
> >  >   d=data[order(data$ID,-data$Type),]
> >  >   d[!duplicated(d$ID),]
> >
> > Does the "-data$Type" argument to the order function work?
> >
> > --
> >  David
> >
> >  -----------------------------------------------------
> >  David Huffer, Ph.D.               Senior Statistician
> >  CSOSA/Washington, DC           david.huffer@csosa.gov
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> > http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
> >
>
> --
> View this message in context:
> http://www.nabble.com/by-group-processing-tp23417208p23453688.html
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>
> ______________________________________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide
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>



-- 
Jun Shen PhD
PK/PD Scientist
BioPharma Services
Millipore Corporation
15 Research Park Dr.
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