On Thu, Apr 26, 2018 at 6:28 AM, Spencer Graves <spencer.gra...@effectivedefense.org> wrote: > > > On 2018-04-26 07:11, Jose A Guijarro wrote: >> >> El 25/04/18 a las 20:21, Duncan Murdoch escribió: >>> >>> On 25/04/2018 1:32 PM, Sarah Goslee wrote: >>>> >>>> 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. >>> >>> >>> That's one good way to do it. But it is possible to change directory and >>> change back at the end of the example. For example, >>> >>> wd <- tempdir() >>> savedir <- setwd(wd) >>> >>> ... # the original code that writes and reads in the current dir >>> >>> setwd(savedir) >>> >>> There's a worry that an error in the middle of the code will leave the >>> user in the wrong place. If that's really unlikely to happen, then this >>> code is a little simpler than Sarah's suggestion. >>> >>> If it is likely, you can use tryCatch(..., finally = setwd(savedir)), but >>> I think Sarah's solution would be preferable in most cases: many users will >>> not understand what tryCatch() does. > > > > Hi, Duncan, et al.: > > > Under what circumstances should one also use "on.exit": > > > wd <- tempdir() > savedir <- setwd(wd) > on.exit(setwd(savedir))? > > > Even senior R programmers may miss a failure mode. In a function, > this works well: I don't need to remember to "setwd(savedir)" later in the > code, which could be a problem if I have multiple exit points. I don't know > how it would work in a vignette or the examples section of a *.Rd file. > tryCatch(..., finally = setwd(savedir)) condenses this into one line ... and > is too terse for me in many cases.
FWIW, it can also be used in a local() call, e.g. local({ wd <- tempdir() savedir <- setwd(wd) on.exit(setwd(savedir)) [...] }) /Henrik > > > Spencer Graves > > >>> >>> Duncan Murdoch >> >> >> Many thanks for the suggestion! In this way I only need to apply slight >> changes in the examples and can avoid modifying all read/writes along the >> package. I will try this approach and see if it passes the CRAN checks. >> >> Jose >> >>> >>>> >>>> Sarah >>>> >>>> >>>> On Wed, Apr 25, 2018 at 12:30 PM, Jose A Guijarro <jguijar...@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 >>>>> >>>> >>>> >>> >> >> ______________________________________________ >> R-package-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-package-devel > > > ______________________________________________ > R-package-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-package-devel ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel