Berwin A Turlach wrote:
> G'day David,
>
> On Tue, 10 Feb 2009 13:23:50 +0100
> David Croll <david.cr...@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
as.data.frame(as.list(pos.to.env(2)))
or ...as.environment("mat")
I wouldn't recommend using <<- like that though; the consequences of
spelling mistakes on the LHS are a bit scary. If you must, consider
with(pos.to.env(2),{
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.dalga...@biostat.ku.dk) FAX: (+45) 35327907
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