R devel - May 2014 - Access variable in attached but removed object

How can I access an object in an attached but deleted environment, when
the object also exists in the .GolbalEnv?

I hope the example below makes the question clear:

--8<---------------cut here---------------start------------->8---
tmp <- attach(what=NULL, name="org:variables")
tmp$test = 13
rm(tmp)
test
# > 13
test <- 24
test
# > 24
ls(all=TRUE)
# > character(0)
# 
# how can I access the variable test in the object org:variables in the
# search path?
#
rm(test)
test
# > 13
--8<---------------cut here---------------end--------------->8---

Any suggestions?

Thanks,

Rainer

-- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology,
UCT), Dipl. Phys. (Germany)

Centre of Excellence for Invasion Biology
Stellenbosch University
South Africa

Tel :       +33 - (0)9 53 10 27 44
Cell:       +33 - (0)6 85 62 59 98
Fax :       +33 - (0)9 58 10 27 44

Fax (D):    +49 - (0)3 21 21 25 22 44

email:      Rainer at krugs.de

Skype:      RMkrug

PGP: 0x0F52F982
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On 09/05/2014, 6:54 AM, Rainer M Krug wrote:
>
> How can I access an object in an attached but deleted environment, when
> the object also exists in the .GolbalEnv?
Attaching a variable to the search list generally makes a copy of it, so 
it can't be "attached but deleted".  However, "making a
copy" of an
environment just copies the reference to it, so your environment still 
exists on the search list, it just doesn't have a name in the global 
environment.
>
> I hope the example below makes the question clear:
>
> --8<---------------cut here---------------start------------->8---
> tmp <- attach(what=NULL, name="org:variables")
> tmp$test = 13
> rm(tmp)
> test
> # > 13
> test <- 24
> test
> # > 24
> ls(all=TRUE)
> # > character(0)
I don't know why you would have seen character(0) here.  You should have 
seen "test" in the list, because you created it a couple of lines
earlier.
> #
> # how can I access the variable test in the object org:variables in the
> # search path?
> #
> rm(test)
> test
> # > 13
> --8<---------------cut here---------------end--------------->8---
>
> Any suggestions?
You can use assign, or get a reference to the environment using 
as.environment("org:variables"), and access it within that.  For
example,

assign("test", 24, pos="org:variables")

or

e <- as.environment("org:variables")
e$test <- 24

Duncan Murdoch