[R] Odp: Returning a vector from by

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 03.11.2008 12:31:31:

> Hello,
> 
> I am trying to return a vector from a simply by but I cannot get it
> working, even using simplify=TRUE.
> 
> res <- data.frame(ID=c("a","a","a","b","b"),Score=c(0,1,2,0,1))
> yoda <- by(res$Score,res$ID,max,simplify=T)
> class(yoda)
> [1] "by"
> 
> I would like it to return a vector with the names as the ID column.  The
> only way I could work out how to do this was
> 
> result <- as.vector(yoda)
> names(result) <- names(yoda)
> result
> a b
> 2 1

Maybe tapply?

yoda <- tapply(res$Score,res$ID,max,simplify=T)

Regards

Petr

> 
> Is there a better way?
> 
> Thanks
> 
> Dan
> 
> -- 
> **************************************************************
> Daniel Brewer, Ph.D.
> 
> Institute of Cancer Research
> Molecular Carcinogenesis
> Email: daniel.brewer at icr.ac.uk
> **************************************************************
> 
> The Institute of Cancer Research: Royal Cancer Hospital, a charitable 
Company 
> Limited by Guarantee, Registered in England under Company No. 534147 
with its 
> Registered Office at 123 Old Brompton Road, London SW7 3RP.
> 
> This e-mail message is confidential and for use by the a...{{dropped:2}}
> 
> ______________________________________________
> R-help at 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.