[R] Obtaining variable's names from a list of variables

[Monsieur Do]

Thank you for your answers. Problem solved. Eik's cue to all.names(match.call())[-1] was particularly enlightning!

Do
 

> De : Eik Vettorazzi
[mailto:E.Vettorazzi at uke.uni-hamburg.de]
> Envoyé : 17 août 2011 08:46
> À : Monsieur Do
> Cc : r-help at r-project.org
> Objet : Re: [R] Obtaining variable's names
from a list of variables
> 
> Hi,
> there is no
direct way, since
> listVar
<- list(age,sex)
> creates a
unnamed list, as can be seen by
> names(listVar)
#or
> str(listVar)
> 
> You can do
sth like
> listVar
<- list(age=age,sex=sex) # or
> listVar2
<- list(age,sex)
> names(listVar2)<-c("age","sex")
> 
> and
afterwards access them using names().
> 
> Or you
write your own list function using its call to name the returned object,
> as in
> 
> my.list<-function(...){
>  tmp<-list(...)
>  names(tmp)<-all.names(match.call())[-1]
>  tmp
> }
> attach(iris)
> a<-my.list(Sepal.Length,Sepal.Width)
> 
> hth.
> 
> Am
17.08.2011 08:46, schrieb Monsieur Do:
> > Say I
have a list of variables,
> >
> >
listVar <- list(age,sex)
> >
> > I am
looking for a way to either
> >
> > 1-
create a vector c("age","sex") from it, or
> > 2- get
the names one by one in a for loop such as these
> >
> >     a)  for (i in 1:length(listVar)) rownames(result)[i] <- ???
> >
> >     b)  for(i in listVar) print (variable's name)
> >
> >
> > Any
help much appreciated.
> >         [[alternative HTML version deleted]]
> >
> >
> >
> >
> >
______________________________________________
> > R-help at r-project.orgmailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE
do read the posting guide
> > http://www.R-project.org/posting-guide.html
> > and
provide commented, minimal, self-contained, reproducible code.
> 
> --
> Eik
Vettorazzi
> Institut
für Medizinische Biometrie und Epidemiologie Universitätsklinikum
> Hamburg-Eppendorf
> 
> Martinistr.
52
> 20246
Hamburg
> 
> T
++49/40/7410-58243
> F
++49/40/7410-57790