[R-pkg-devel] How to write example results to a tempdir()?

Uwe Ligges ligges at statistik.tu-dortmund.de
Wed Apr 25 20:02:26 CEST 2018

On 25.04.2018 19:45, Jose A Guijarro wrote:
> Many thanks for your advise, Sarah!
> I will try to implement it. (Now I will have to change all my reading and
> writing sentences of all my functions, because they read/write from/to
> the users working directory...)

Whcih is OK if the user specifies some filename.

Uwe Ligges

> Best regards,
>      Jose
> El 25/04/18 a las 19:32, Sarah Goslee escribió:
>> Don't change the working directory! That has all kinds of unpleasant
>> side effects for the unsuspecting user, possibly even more so than
>> writing to a file.
>> Instead, write the file to the temp directory, and read it from there, 
>> with e.g.
>> wd <- tempdir()
>> write(dat, file.path(wd, 'Ttest_1981-2000.dat'))
>> Using file.path() means that the appropriate path delimiter for that
>> OS will be used.
>> Sarah
>> On Wed, Apr 25, 2018 at 12:30 PM, Jose A Guijarro 
>> <jguijarrop at aemet.es> wrote:
>>> Dear all,
>>> I am struggling to update my package climatol from version 3.0 to 3.1.
>>> The old version had all examples under a "dontrun" section because they
>>> needed files created by other examples that the user had to run first.
>>> As this is not acceptable anymore, I made the examples runnable and
>>> prepared small ad-hoc datasets, but then writing files to the user space
>>> is against the CRAN policy rules, and I was suggested to run them on a
>>> temporal directory. Therefore I changed all my examples to read/write
>>> files to a tempdir(), as in:
>>> \examples{
>>> #Set a temporal working directory and write input files:
>>> wd <- tempdir()
>>> setwd(wd)
>>> data(Ttest) #(This loads matrix 'dat' and data.frame 'est.c')
>>> write(dat,'Ttest_1981-2000.dat')
>>> write.table(est.c,'Ttest_1981-2000.est',row.names=FALSE,col.names=FALSE)
>>> rm(dat,est.c) #remove loaded data from memory space
>>> #Now run the example:
>>> dd2m('Ttest',1981,2000)
>>> #Input and output files can be found in directory:
>>> print(wd)
>>> }
>>> But now CRAN checks return this warning ten times (one for every example
>>> in the package):
>>> Warning: working directory was changed to ‘/tmp/RtmpWSRK2F’, resetting
>>> Any hint on how to solve the problem will be highly appreciated...
>>> Jose

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