[R] access data inside package

[Duncan Murdoch]

On 20/01/2008 3:21 PM, Dan Kelley wrote:
> The technique
>     d <- get("d", pos=globalenv())
> doesn't work for me.  It just says that it cannot get "d", even though I
> have a data/d.rda file.
> 
> Do I have to do something special with namespaces, to find it?  
> 
> PS. a possibly-related link is as follows.
> 
> http://www.nabble.com/how-to-make-read-only-data-frames--tp14756183p14756183.html

If you put it in data/d.rda, then it doesn't get loaded until you 
request it via a call to data().  That's why the get() doesn't work.

I think you have two choices:

In some file in your R directory, create the object d.  You might do 
this by putting the file into inst/something and loading it from there, 
or you might just include R source that creates it.

Alternatively, put it in the special sysdata.rda file in the R 
directory.  See Writing R Extensions "Package Subdirectories" for 
instructions.

You probably want to specify LazyLoad: yes for your package, so that 
objects don't take up memory until actually referenced.

In either of these cases, the object d will be visible to users as soon 
as your package is loaded.  If you don't want that, you should use a 
namespace for your package.

Duncan Murdoch