[R] RE: variable number of variables in data frames

[Peter Dalgaard BSA]

"Henrik Bengtsson" <henrikb at braju.com> writes:

> Kevin, you can treat data frames as matrices, i.e. you can do
> 
>   dat <- matrix(c(2,1,1,1, 1,1,1,1), 2, 4)
>   D <- as.data.frame(dat)
>   for (i in 1:ncol(D)) 
>     D[,i] <- factor(D[,i], 1:2)
..
> > for (i in my.factor.columns) {
> >   D$Vi <- factor(D$Vi, 1:my.nlevels[i])
> > }

Also,

> D[1:2]<-lapply(D[1:2],factor,levels=1:2)
> summary(D)
 V1    V2          V3          V4   
 1:1   1:2   Min.   :1   Min.   :1  
 2:1   2:0   1st Qu.:1   1st Qu.:1  
             Median :1   Median :1  
             Mean   :1   Mean   :1  
             3rd Qu.:1   3rd Qu.:1  
             Max.   :1   Max.   :1  


-- 
   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
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._