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

[Eik Vettorazzi]

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]]
> 
> 
> 
> 
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-- 
Eik Vettorazzi
Institut für Medizinische Biometrie und Epidemiologie
Universitätsklinikum Hamburg-Eppendorf

Martinistr. 52
20246 Hamburg

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