It is just a simple version of 'factor'. The only speed advantage it might have is that it checks to see if it is a factor first. Here is the definition: )> as.factor function (x) if (is.factor(x)) x else factor(x) <environment: namespace:base> You can always list out what the function does to get a better understanding of how it works.
On Wed, Apr 8, 2009 at 8:16 AM, Heinz Tuechler <tuechler at gmx.at> wrote:
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
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-- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve?
Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve?