[R] Odp: Problem with retrieving updated variables after attach()
P.Dalgaard at biostat.ku.dk
Tue Feb 10 14:18:26 CET 2009
Berwin A Turlach wrote:
> G'day David,
> On Tue, 10 Feb 2009 13:23:50 +0100
> David Croll <david.croll at gmx.ch> wrote:
>> Well, I knew that attach() only creates a copy of the variables in
>> the search path.
>> What I wanted to ask was how to *retrieve* that copy...
>> > mat
>> id age
>> 1 NA NA
>> 2 NA NA
>> 3 NA NA
>> 4 NA NA
>> 5 NA NA
>> > attach(mat)
>> > id <<- sample(100,5)
>> > age <<- rnorm(5,mean=30)
>> How can I make a new data frame out of the id and age that were
>> changed above?
> R> new.df <- data.frame(id,age)
> Or, perhaps more automatic:
> R> new.df <- do.call(data.frame, sapply(ls(pos=2), as.name))
> Is this what you are after?
There is also
I wouldn't recommend using <<- like that though; the consequences of
spelling mistakes on the LHS are a bit scary. If you must, consider
id <- sample(100,5)
age <- rnorm(5,mean=30)
or better, modify before attach, using within() or transform().
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
More information about the R-help