[R] conversion of a data.frame of numerics to a data.frame of factors

[Prof Brian Ripley]

On Sat, 9 Oct 2004, Patrick Giraudoux wrote:

mydf[] <- lapply(mydf, as.factor)

would appear to be what you want.

For a matrix, I presume you want a factor matrix as the result.  Something 
like

my <- matrix(1:12, 3, 4)
dmy <- dim(my)
my <- as.factor(my)
dim(my) <- dmy
my

which does not print as a matrix but is one.  If you want a data frame 
result, convert to a data frame first.

> Hi,
> 
> I am trying to convert a data.frame of numerics (this could be a matrix
> as well in this case) into a data.frame of factors.
> 
> I did it in a way that is less than direct...
> 
> myforet2<-t(myforet)
> for (i in 1:length(myforet2[1,])) {
>     if (i == 1)myforetfact<-list(as.factor(myforet2[,i]))
>     else myforetfact<-c(myforetfact,list(as.factor(myforet2[,i])))
> }
> myforetfact<-data.frame(myforetfact)
> names(myforetfact)<-row.names(myforet)
> 
> Here again, I wonder if there are no easier way to go through.... (the loop is not "R" style, for the least). However, I cannot do
> it otherway so far...
> 
> Cheers,
> 
> Patrick
> 
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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