[R] memory blues

[Claudia Tebaldi]

On Mon, 9 Jul 2001, Laurent Gautier wrote:

> Dear all,
> 
> 
> 
> I would like to know if the following behaviour is what one would expect ?
> (I am running R-1.2.3 (I know I'd better upgrade) under Linux).
> 
> It seems a data.frame with only one column becomes a special case.... and
> I cannot figure out why (I'd see no problem in being told to rtfm, I could not
> find
> anything about that in the help pages)
> 
> 
> > a  <- data.frame(c(1:3),row.names=c("c","a","b"))
> > a
>   c.1.3.
> c      1
> a      2
> b      3
> > a[order(row.names(a)),]
> [1] 2 3 1
> 
> 
> ...kinda odd, especially since the following give what I'd expect....
> 
> 
> > a  <- data.frame(cbind(c(1:3),c(3:5)),row.names=c("c","a","b"))
> > a
>   X1 X2
> c  1  3
> a  2  4
> b  3  5
> > a[order(row.names(a)),]
>   X1 X2
> a  2  4
> b  3  5
> c  1  3
> 
> 
> 
> Cheers,
> 
> 
> Laurent
> 
> 
> --
> Laurent Gautier                 CBS, Building 208, DTU
> PhD. Student                    D-2800 Lyngby,Denmark
> tel: +45 45 25 24 85            http://www.cbs.dtu.dk/laurent
> 
> 
> 

Are you puzzled by the naming of the columns or by the loss of dimensions?
For the first you already got an explanation, but in case you are
wondering how to keep a single column of a data.frame  in the same
"ontological" category:



a[order(row.names(a)),,drop=F]  


maintains the subscripted a (assuming it is your first object, the data
frame with one column) in the data.frame class.

If you knew all this I apologize for the unwanted/unneeded lesson. 




 


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