R help - Mar 2001 - How to coerce data frame elements into factors?

Greetings -

In trying to do a multiple correspondence analysis, I need to coerce a
data frame such that each of its columns will be a factor.  Can someone
offer advice on how to make this happen?  I've tried this:
> logic.resources.f.df<-apply(logics.resources.df, 2, factor)
but:
> is.factor(logic.resources.f.df$interests)
[1] FALSE


I've also tried individually,
> foo<-data.frame(c(factor(mediate), factor(morality)))
but still,
> is.factor(foo$mediate)
[1] FALSE


Thanks for any assistance.

----------------------------------------------------------------------
Andrew J Perrin - Ph.D. Candidate, UC Berkeley, Dept. of Sociology  
Chapel Hill, North Carolina, USA - http://demog.berkeley.edu/~aperrin
        aperrin at socrates.berkeley.edu - aperrin at igc.apc.org


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Andrew Perrin <aperrin at socrates.berkeley.edu> writes:
> Greetings -
> 
> In trying to do a multiple correspondence analysis, I need to coerce a
> data frame such that each of its columns will be a factor.  Can someone
> offer advice on how to make this happen?  I've tried this:
> 
> > logic.resources.f.df<-apply(logics.resources.df, 2, factor)
> 
> but:
> 
> > is.factor(logic.resources.f.df$interests)
> [1] FALSE
apply will give you a vector or array, so you're doing is.factor(NULL) 
> 
> 
> I've also tried individually,
> 
> > foo<-data.frame(c(factor(mediate), factor(morality)))
> > is.factor(foo$mediate)
> [1] FALSE
What gives you the idea that that would have a component called
"mediate"? 
> x<-1:0
> y<-0:1
> data.frame(c(factor(x),factor(y)))
  c.factor.x...factor.y..
1                       2
2                       1
3                       1
4                       2

Try this:
> d<-data.frame(a=0:1,b=1:0)
> d<-as.data.frame(lapply(d,factor)) 
-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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