veraf at clemson.edu
2009-Oct-12 18:30 UTC
[Rd] names drop for columns from data.frame (PR#14002)
Full_Name: Francisco Vera
Version: 2.9.2
OS: Windows
Submission from: (NULL) (74.248.242.164)
Run the following commands:
a<-data.frame(x=1:2,y=3:4,row.names=c("i","j"))
names(a$x)
names(a[,1])
For names(a$x) I get NULL instead of c("i","j"). Same thing
happens with
names(a[,1]). It works fine for rows, i.e., names(a[1,]) gives what is supposed
to.
It also works fine for matrices. If you issue the commands
b<-matrix(1:4,ncol=2,dimnames=list(c("x","y"),c("i","j")))
names(b[,1])
names(b[1,])
Thanks
Have you tried names(a[,1,drop=FALSE])?
Then have a look at help("[").
-Peter
veraf at clemson.edu wrote:> Full_Name: Francisco Vera
> Version: 2.9.2
> OS: Windows
> Submission from: (NULL) (74.248.242.164)
>
>
> Run the following commands:
>
> a<-data.frame(x=1:2,y=3:4,row.names=c("i","j"))
> names(a$x)
> names(a[,1])
>
> For names(a$x) I get NULL instead of c("i","j"). Same
thing happens with
> names(a[,1]). It works fine for rows, i.e., names(a[1,]) gives what is
supposed
> to.
>
> It also works fine for matrices. If you issue the commands
>
b<-matrix(1:4,ncol=2,dimnames=list(c("x","y"),c("i","j")))
> names(b[,1])
> names(b[1,])
>
> Thanks
>
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> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>
--
Peter Ehlers
University of Calgary