R help - Mar 2013 - Obtaining the internal integer codes of a factor XXXX

Hi everyone,

I understand the process of obtaining the internal integer codes for
the raw values of a factor (using as.numeric() as below), but what is
the best way to obtain these codes for the levels() of a factor (since
the as.numeric() results don't really make clear which code maps to
which level)?


fdata<-factor(c("b","b","c","a","b","c"),labels=c("I","II","III"))
fdata
levels(fdata)

as.numeric(fdata)


I thought something like this would make sense and work, but it throws an error:

as.numeric(levels(fdata))

Thanks!

Dan

Why do you think you need to do this?
(Feel free to ignore, however).

-- Bert

On Mon, Mar 25, 2013 at 8:37 AM, Dan Abner <dan.abner99@gmail.com> wrote:
> Hi everyone,
>
> I understand the process of obtaining the internal integer codes for
> the raw values of a factor (using as.numeric() as below), but what is
> the best way to obtain these codes for the levels() of a factor (since
> the as.numeric() results don't really make clear which code maps to
> which level)?
>
>
>
fdata<-factor(c("b","b","c","a","b","c"),labels=c("I","II","III"))
> fdata
> levels(fdata)
>
> as.numeric(fdata)
>
>
> I thought something like this would make sense and work, but it throws an
> error:
>
> as.numeric(levels(fdata))
>
> Thanks!
>
> Dan
>
> ______________________________________________
> R-help@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.
>


-- 

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm

	[[alternative HTML version deleted]]

On 25/03/2013 11:37 AM, Dan Abner wrote:
> Hi everyone,
>
> I understand the process of obtaining the internal integer codes for
> the raw values of a factor (using as.numeric() as below), but what is
> the best way to obtain these codes for the levels() of a factor (since
> the as.numeric() results don't really make clear which code maps to
> which level)?
>
>
>
fdata<-factor(c("b","b","c","a","b","c"),labels=c("I","II","III"))
> fdata
> levels(fdata)
>
> as.numeric(fdata)
>
>
> I thought something like this would make sense and work, but it throws an
error:
>
> as.numeric(levels(fdata))
seq_len(length(levels(fdata)))

will give you the numeric codes for the levels.  They are simply 1:3 in 
your example above.  (Or perhaps I misunderstood your question?)

Duncan Murdoch

Hello,

Though I have the same doubt as Bert, the following seems to make more 
sense.

seq_along(levels(fdata))


Hope this helps,

Rui Barradas

Em 25-03-2013 15:37, Dan Abner escreveu:
> Hi everyone,
>
> I understand the process of obtaining the internal integer codes for
> the raw values of a factor (using as.numeric() as below), but what is
> the best way to obtain these codes for the levels() of a factor (since
> the as.numeric() results don't really make clear which code maps to
> which level)?
>
>
>
fdata<-factor(c("b","b","c","a","b","c"),labels=c("I","II","III"))
> fdata
> levels(fdata)
>
> as.numeric(fdata)
>
>
> I thought something like this would make sense and work, but it throws an
error:
>
> as.numeric(levels(fdata))
>
> Thanks!
>
> Dan
>
> ______________________________________________
> 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.
>