Thank you all so much! You are unbelievable!

Cheers,
Lauri

2007/3/20, Adaikalavan Ramasamy <ramasamy@cancer.org.uk>:
>
> Here is yet another solution. This one uses by() which generates nice
> visual output.
>
> score <- data.frame(
>   id      = c('001','001','001','002','003','003'),
>   math    = c(80,75,70,65,65,70),
>   reading = c(65,70,88,NA,90,NA)
> )
>
> out <- by( score, score$id, tail, n=2 )
> # score$id: 001
> #    id math reading
> # 2 001   75      70
> # 3 001   70      88
> # ------------------------------------------------------------
> # score$id: 002
> #    id math reading
> # 4 002   65      NA
> # ------------------------------------------------------------
> # score$id: 003
> #    id math reading
> # 5 003   65      90
> # 6 003   70      NA
>
>
> And if you want to put it back into a data frame, use
>
> do.call( "rbind", as.list(out) )
> #        id math reading
> # 001.2 001   75      70
> # 001.3 001   70      88
> # 002   002   65      NA
> # 003.5 003   65      90
> # 003.6 003   70      NA
>
> Ignore the rownames here.
>
> HTH, Adai
>
>
> Lauri Nikkinen wrote:
> > Hi R-users,
> >
> > Following this post
> http://tolstoy.newcastle.edu.au/R/help/06/06/28965.html ,
> > how do I get last two rows (or six or ten) by id group out of the data
> > frame? Here the example gives just the last row.
> >
> > Sincere thanks,
> > Lauri
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@stat.math.ethz.ch 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.
> >
> >
> >
>
>

	[[alternative HTML version deleted]]

