[R] factor to numeric in data.frame

[Heinz Tuechler]

At 07:15 02.04.2005 -0500, Gabor Grothendieck wrote:
>Try this:
>
>data.matrix(df.f12)
>
Perfect! This is exactly what I needed.
 
Many thanks,
Heinz Tüchler

>On Apr 2, 2005 6:01 AM, Heinz Tuechler <tuechler at gmx.at> wrote:
>> Dear All,
>> 
>> Assume I have a data.frame that contains also factors and I would like to
>> get another data.frame containing the factors as numeric vectors, to apply
>> functions like sapply(..., median) on them.
>> I read the warning concerning as.numeric or unclass, but in my case this
>> makes sense, because the factor levels are properly ordered.
>> I can do it, if I write for each single column "unclass(...), but I would
>> like to use indexing, e.g. unclass(df[1:10]).
>> Is that possible?
>> 
>> Thanks,
>> Heinz Tüchler
>> 
>> ## Example:
>> f1 <- factor(c(rep('c1-low',2),rep('c2-med',5),rep('c3-high',3)))
>> f2 <- factor(c(rep('c1-low',5),rep('c2-low',3),rep('c3-low',2)))
>> df.f12 <- data.frame(f1,f2) # data.frame containing factors
>> 
>> ## this does work
>> df.f12.num <- data.frame(unclass(df.f12[[1]]),unclass(df.f12[[2]]))
>> df.f12.num
>> ## this does not work
>> df.f12.num <- data.frame(unclass(df.f12[[1:2]]))
>> df.f12.num
>> ## this does not work
>> df.f12.num <- data.frame(unclass(df.f12[1:2]))
>> df.f12.num
>> 
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>
>