[R] factor, as.factor and levels

[jim holtman]

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
>>
>
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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