[R] factor, as.factor and levels

[Heinz Tuechler]

Thank you, Jim. I see, the fact that in the documentation you find only
"as.factor(x)" means that it does not accept more arguments.
Does as.factor have speed advantages over factor, or is there a 
different cause for it's existence?

Heinz



At 13:50 08.04.2009, jim holtman wrote:
>as.factor does not accept levels as an argument.  use the first form
>that you have
>
>factor(ch1, levels=ch1)
>
>
>
>On Wed, Apr 8, 2009 at 7:36 AM, Heinz Tuechler <tuechler at gmx.at> wrote:
> > Dear All,
> >
> > to my surprise as.factor does not accept a levels argument. Maybe I did not
> > read the documentation well enough. See the example below. I wanted to use
> > ch1 as factor in the newdata argument of survfit, so I assumed that I could
> > write as.factor(ch1, levels=ch1), since the order should be kept.
> >
> > But as.factor(ch1, levels=ch1) results in the error:
> >
> > Error in as.factor(ch1, levels = ch1) :
> >  unused argument(s) (levels = c("low", "inter", "high"))
> >
> > factor(ch1, levels=ch1) works as I expected.
> > Is it intended that as.factor does not use the levels argument?
> >
> > Thanks,
> >
> > Heinz
> >
> > ch1 <- c('low', 'inter', 'high')
> > factor(ch1)
> > factor(ch1, levels=ch1)
> > as.factor(ch1, levels=ch1)
> >
> >> version
> >               _
> > platform       i386-pc-mingw32
> > arch           i386
> > os             mingw32
> > system         i386, mingw32
> > status         Patched
> > major          2
> > minor          8.1
> > year           2009
> > month          03
> > day            13
> > svn rev        48132
> > language       R
> > version.string R version 2.8.1 Patched (2009-03-13 r48132)
> >> sessionInfo()
> > R version 2.8.1 Patched (2009-03-13 r48132)
> > i386-pc-mingw32
> >
> > locale:
> > 
> LC_COLLATE=German_Switzerland.1252;LC_CTYPE=German_Switzerland.1252;LC_MONETARY=German_Switzerland.1252;LC_NUMERIC=C;LC_TIME=German_Switzerland.1252
> >
> > attached base packages:
> > [1] splines   stats     graphics  grDevices utils     datasets  methods
> > [8] base
> >
> > other attached packages:
> > [1] survival_2.34-1 car_1.2-12      gmodels_2.14.1  gdata_2.4.2
> > [5] Hmisc_3.5-2
> >
> > loaded via a namespace (and not attached):
> > [1] cluster_1.11.12 grid_2.8.1      gtools_2.5.0-1  lattice_0.17-20
> > [5] MASS_7.2-46
> >>
> >
> > ______________________________________________
> > 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.
> >
>
>
>
>--
>Jim Holtman
>Cincinnati, OH
>+1 513 646 9390
>
>What is the problem that you are trying to solve?