Well, it would have helped if you'd given us an example of what
exactly you did, but here's a working solution.
> Orthodont <- data.frame(age = 1:6, sex = factor(c("m", "f", "m", "f", "m",
> "f")))
> str(Orthodont)
'data.frame': 6 obs. of 2 variables:
$ age: int 1 2 3 4 5 6
$ sex: Factor w/ 2 levels "f","m": 2 1 2 1 2 1
> Orthodont$age <- factor(Orthodont$age)
> str(Orthodont)
'data.frame': 6 obs. of 2 variables:
$ age: Factor w/ 6 levels "1","2","3","4",..: 1 2 3 4 5 6
$ sex: Factor w/ 2 levels "f","m": 2 1 2 1 2 1
> Orthodont$sex <- c(1, -1)[as.numeric(Orthodont$sex)]
> str(Orthodont)
'data.frame': 6 obs. of 2 variables:
$ age: Factor w/ 6 levels "1","2","3","4",..: 1 2 3 4 5 6
$ sex: num -1 1 -1 1 -1 1
Note that the last one depends on the ordering of your male and
female factors. Here "f" is 1 and "m" is 2, so I used c(1, -1) - the
desired values for "f" and "m" in numeric order by factor.
Sarah
On Mon, Mar 16, 2009 at 5:55 AM, Katya Mauff <katya.ma...@uct.ac.za> wrote:
> Hi all
>
> I’m in desperate need of help. I’m working with a grouped data object, called
> Orthodont in the nlme package in R, and am trying to fit various models
> (learning methods for my thesis), but one of the variables in the object is
> numeric, (age) and I need it to be a factor. I’ve tried:
> as.factor(Orthodont$age)
> as.factor(as.character(Orthodont$age))
>
> and various other things, but when I then check the class of the variables
> using
> sapply(Orthodont, data.class)
> I still get age as numeric…
>
> Also, sex is a factor, but for the models I’m fitting I need it to be coded
> as a binary variable with values (-1) for males and (+1) for females, and I
> don’t know how to do this either. Please help-I’m losing my mind….!
>
>
>
--
Sarah Goslee
http://www.functionaldiversity.org
______________________________________________
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.
