[R] assigning to a list in a package environment

Sean Davis sdavis2 at mail.nih.gov
Thu May 12 16:27:56 CEST 2005


On May 12, 2005, at 10:09 AM, Gabor Grothendieck wrote:

> On 5/11/05, Sean Davis <sdavis2 at mail.nih.gov> wrote:
>> I have a list in a package environment
>>
>> assign('refflat',list(),pos='package:locPkg')
>>
>> to which I would like to make assignments like:
>>
>> refflat[['a']] <- read.table('fileA.txt')
>> refflat[['b']] <- read.table('fileB.txt')
>>
>> I am doing this to guard against a local version of refflat hanging
>> around, as I want to refresh it with each new session (and so, want to
>> store it in the package environment).  I just can't quite get hot to
>> make that work so that I am storing to the package:refflat rather than
>> any in .GlobalEnv.
>
> Try this:
>
> locPkg <- as.environment("package:locPkg")
> locPkg$refflat <- list()
> locPkg$refflat[["a"]] <- read.table("fileA.txt")
>

Gabor,

Thanks.  That will do the trick, I think.  Now, just one more question 
as followup if I may?  If I am executing a function that was defined in 
locPkg, how can I determine dynamically what environment I am in?  Them 
I could do something like

myFun <- function (x) {
   # code
   locPkg <- as.environment( .... )
   # more code
}

where '....' is replaced dynamically by the package environment of the 
package in which the function myFun is defined.  The goal is to make 
the code a bit more portable.

Again, thanks for the help.

Sean




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