file_out replacement

[ghost]

Hello!

I remember drake having file_out, and I know targets has a format = "file" to replace the file_in. I was wondering if there was an equivalent in targets or it's become redundant?

Kind Regards,

Marc

[wlandau]

All files in targets are dynamic files: supply format = "file" to tar_target() and return a character vector of the file/directory paths you want to track (one hash for all of them). Whether you are describing input files or output files, the interface is the same:

• Input files: https://books.ropensci.org/targets/files.html#external-input-files
• Output files: https://books.ropensci.org/targets/files.html#external-output-files

drake also had dynamic files, but it barely worked when combined with all the other features: https://books.ropensci.org/drake/plans.html#dynamic-files.

There is no file_out() in targets because new drake users always found it confusing because file_out() needs to know the literal file path in advance.

[ghost]

Thank you,

So if I would like to save a file in my cache, and export it, I should use two separate targets is what I'm understanding.

[wlandau]

I usually do. If the duplication takes up too much storage, you could write a single target to run the computation and save the external file all in one go (avoids saving to _targets/objects/).