Odp: Problem with retrieving updated variables after attach()
Hi r-help-bounces at r-project.org napsal dne 10.02.2009 13:57:44:
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?
The question is why he wants to do this? I do not see the point of attaching data frame, changing something in attached frame and then keeping a new copy. Why not mat new.mat <- mat new.mat[,n1] <- some change new.mat[,n2] <- some other change without tricky use of attach if he wants to keep the changed copy. Regards Petr
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