[R-pkg-devel] Writing to files without altering working directory in R package
On 03/05/2019 6:33 p.m., Jarrett Phillips wrote:
Hello,
My R package has a function with an argument to specify whether numerical
results should be outputted to a CSV file.
CRAN policy stipulates verbatim that
Packages should not write in the user?s home filespace (including
clipboards), nor anywhere else on the file system apart from the R
session?s temporary directory (or during installation in the location
pointed to by TMPDIR: and such usage should be cleaned up). Installing into
the system?s R installation (e.g., scripts to its bin directory) is not
allowed.
I know I should use tempdir() within my package function, but I've not seen
any examples on how this is best done within existing R packages.
Within my package documentation examples for my function, I have the lines:
\dontshow{.oldwd <- setwd(tempdir())}
... some R code ...
\dontshow{setwd(.oldwd)}
but I have been informed that this is not the accepted way.
Any ideas from the community on how do do this properly?
Use the tempfile() function to generate a filename in the temporary directory. You might want to use the "pattern" or "fileext" arguments, but don't change the "tmpdir" argument. Then write to that file. For example, filename <- tempfile(fileext = ".csv") write.csv(df, filename) It's a good idea to clean up afterwards using unlink(filename)