Murray Jorgensen <maj at waikato.ac.nz> writes:
> It is not uncommon to want to coarsen a factor by grouping levels
> together. I have found one way to do this in R:
>
> > sites
> [1] F A A D A A B F C F A D E E D C F A E D F C E D E F F D B C
> Levels: A B C D E F
> > regions <- list(I = c("A","B","C"),
II = "D", III = c("E","F"))
> > library(Epi)
> > region <- Relevel(sites,regions)
> > region
> [1] III I I II I I I III I III I II III III II I
> III I III
> [20] II III I III II III III III II I I
> Levels: I II III
>
> However this seems like using a sledgehammer to crack a nut. Can someone
> suggest a simpler way to do this task?
Yes,
> regions <- list(I = c("A","B","C"), II =
"D", III = c("E","F"))
> levels(sites) <- regions
> sites
[1] III I I II I I I III I III I II III III II I III I III
[20] II III I III II III III III II I I
Levels: I II III
--
O__ ---- Peter Dalgaard ??ster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907