[R] lapply() not converting columns to factors (no error message)

[A Singh]

Dear List,

I'm having a curious problem with lapply(). I've used it before to convert 
a subset of columns in my dataframe, to factors, and its worked. But now, 
on re-running the identical code as before it just doesn't convert the 
columns into factors at all.

As far as I can see I've done nothing different, and its strange that it 
shouldn't do the action.

Has anybody come across this before? Any input on this strange issue much 
appreciated..

Hope I haven't missed something obvious.

Thanks a lot,

Aditi

(P.s.- I've tried converting columns one by one to factors this time, and 
that works.

>P1L55<-factor(P1L55)
>levels(P1L55)
>[1] "0" "1"

Code:

prm<-read.table("P:\\.....  .csv", header=T, ...sep=",", ...)

prmdf<-data.frame(prm)

prmdf[2:13]<-lapply(prmdf[2:13], factor) ## action performed, no error 
message

##I tried to pick random columns and check

>levels(P1L55)
>NULL

>is.factor(P1L96)
>FALSE


----------------------
A Singh
Aditi.Singh at bristol.ac.uk
School of Biological Sciences
University of Bristol