[R-pkg-devel] RData files with identical objects in package

On 14 Jan 2019, at 07:10 , Troels Ring <tring at gvdnet.dk> wrote:

Thank you so much! Perhaps it could be mentioned in the official 
documentation on writing R extensions - even if - if I can read 
English - the default is to avoid "lazyData" loading - and "laxyData" 
loading is in some opposition to loading using data() - whereas - if 
we use RStudio, and make an R documentation file for data, we have it 
ending with:
\examples{
data(ddd)
## maybe str(ddd) ; plot(ddd) ...
}
\keyword{datasets}

At the same time as "lazyData" is used default in DESCRIPTION ?

1.1.6 Data in packages
The data subdirectory is for data files, either to be made available 
via lazy-loading or for loading using data(). (The choice is made by 
the 'LazyData' field in the DESCRIPTION file: the default is not to do 
so.) It should not be used for other data files needed by the package, 
and the convention has grown up to use directory inst/extdata for such

All best wishes
Troels


-----Oprindelig meddelelse-----
Fra: peter dalgaard <pdalgd at gmail.com>
Sendt: 13. januar 2019 22:00
Til: Troels Ring <tring at gvdnet.dk>
Cc: Michael Dewey <lists at dewey.myzen.co.uk>; package-develop 
<r-package-devel at r-project.org>
Emne: Re: [R-pkg-devel] RData files with identical objects in package

I think it is illegal if you use the lazyload database, because that 
is indexed by name and contains every object that would be created by

This creates an obvious issue if two objects share a name. 

Once you use the lazyload database, loading the package creates an 
environment which is initially full of promises, one for each object.
Evaluating one of these makes the actual object appear in the environment.

Using data() causes the corresponding promise(s) to be created in the 
global environment. IIRC, there is a registry that says which objects 
are created by which arguments to data(), but as they are still taken 
from the lazydata database, the last one created with a given name still

-ps

On 13 Jan 2019, at 14:13 , Troels Ring <tring at gvdnet.dk> wrote:

Thanks a lot - I'm sure you are right that I could just use different 
names but I cannot understand why it could cause problem to have two 
different well formated .RData files in the /data directory both with 
an "x" - is that really illegal? I cannot see it stated in the 
official munual - but it is long (wrting r extensions) -BW Troels

-----Oprindelig meddelelse-----
Fra: Michael Dewey <lists at dewey.myzen.co.uk>
Sendt: 13. januar 2019 12:56
Til: Troels Ring <tring at gvdnet.dk>; package-develop 
<r-package-devel at r-project.org>
Emne: Re: [R-pkg-devel] RData files with identical objects in package

Dear Troels

Perhaps I misunderstand what you are trying to do but would it be 
possible to put each x and y into a list or a dataframe with 
different names and then modify your usgae to pull them from there? 
Then there would be no danger of users getting the wrong x and y

Michael

On 13/01/2019 08:38, Troels Ring wrote:

Dear friends - I have a package under creation making heavy 
calculations on chemical/clinical data and I plan to include as 
"examples" the use of some literature data used in my papers. To 
illustrate what then occurs, I made two RData files consisting only 
of x and y with different values for x and y like

X <- 100

Y <- 1000

save(x,y,file="first.RData")

and then a new x and y in "second" with x <- 45 and y <- 32

When I put these in a "data" directory of a new package without 
further ado in RStudio

Ctrl-shift-L

Ctrl-shift-B



.there is a warning

* installing *source* package 'try' ...

** R

** data

*** moving datasets to lazyload DB

warning: objects 'x', 'y' are created by more than one data call

** byte-compile and prepare package for lazy loading

** help

 converting help for package 'try'

*** installing help indices

   finding HTML links ...    hello

html

done



Now, when I clear the workspace:

ls()

character(0)

devtools::load_all(".")

Loading try

Restarting R session...

library(try)
ls()

character(0)

x   #-- so even if workspace Is empty x is still kept

[1] 45

data(first) # and "first" is not seen x

[1] 45



x is still present - and y



I have been reading and searching in "Writing R extensions" but so 
far didn't find the clue.

Seemingly it is the file with the last name that is assessed - when 
I rename first.RData to "xfile.RData" we get 100 and 1000.

Now and then when running ctrl-shift-L and - B we see



Attaches package: 'try'

The following objects are masked _by_ '.GlobalEnv':
x, y



Sorry for these problems -

BW
Troels


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