[R] Character coerced to factor and I cannot get it back

[Gabor Grothendieck]

Try this:

DF <- data.frame(let = letters[1:3], num = 1:3, stringsAsFactors = FALSE)
str(DF)


On 4/19/07, John Kane <jrkrideau at yahoo.ca> wrote:
>
> --- Tyler Smith <tyler.smith at mail.mcgill.ca> wrote:
>
> > I really need to sit down with the manual and sort
> > factors and classes
> > properly. In your case, I think the problem has
> > something to do with
> > the way a list behaves?  I'm not sure, but if you
> > convert your list to
> > a dataframe it seems to work ok:
> >
> > > dd3 <- as.data.frame(dd1)
> > > typeof(dd3$st)
> > [1] "integer"
> > > class(dd3$st)
> > [1] "factor"
> > > dd3$st <- as.character(dd3$st)
> > > typeof(dd3$st)
> > [1] "character"
> > > class(dd3$st)
> > [1] "character"
> >
> > HTH,
> >
> > Tyler
>
> Seems to work nicely. I had forgotten about
> 'as.data.frame.
>
> I originally thought that it might be a list problem
> too but I don't think so. I set up the example as a
> list since that is the way my real data is being
> imported from csv. However after my original posting I
> went back and tried it with just a dataframe and I'm
> getting the same results. See below.
>
> I even shut down R , reloaded it and detached the two
> extra packages I usually load. Everything is working
> fine but I am doing some things with factors that I
> have never done before and this just makes me a bit
> paranoid.
>
> Thanks very much for the help.
>
>
> EXAMPLE
> dd  <- data.frame(aa <- 1:4, bb <-  letters[1:4],
>         cc <- c(12345, 123456, 45678, 456789))
>
> id  <-  as.character(dd[,3]) ; id
>
> st  <- substring(id, 1,nchar(id)-4 ) ; st
> typeof (st)  ; class(st)
>
> dd1  <-  cbind(dd, st)
>    names(dd1)  <- c("aa","bb","cc","st")
>    dd1
>    typeof(dd1$st); class(dd1$st)
>
> dd2  <-  cbind(dd, as.character(st))
>    names(dd2)  <- c("aa","bb","cc","st")
>    dd2
>    typeof(dd2$st) ;   class(dd2$st)
>
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