[R] A couple of batch mode questions

[Eric Berger]

Some additional comments that might be relevant to people interested in
these topics.

1. For R scripts you should also consider the package littler developed by
Dirk Eddelbuettel, Highly recommended.
For info http://dirk.eddelbuettel.com/code/littler.html or the github
repository.

2. Scripts can be useful both for short calculations, extending the shell,
or for large R jobs that are not interactive and can run unsupervised.
e.g. I have a script that is run automatically on a daily schedule. It
performs a number of calculations and updates a database with the results.

3. When creating a large-ish R project that will run as a script, I still
break the task into smaller tasks which are implemented as R scripts which
are source()'ed into the batch job.
The smaller R scripts are usually developed and debugged in an interactive
environment, such as RStudio.

Best,
Eric


On Wed, Jul 25, 2018 at 7:36 PM, MacQueen, Don via R-help <
r-help using r-project.org> wrote:

> From my perspective, which is a unix-alike perspective, Rscript makes R
> useable in exactly the same way as other unix style scripting languages
> such as perl,  tcsh, bash, etc. This is useful, and a good thing. If I
> remember (and understood) correctly, it is why Rscript was introduced,
> later in R's history than BATCH.
>
> Scripts run using Rscript can be (slightly) more self-contained, which I
> suppose might or might not be an advantage, depending on one's needs:
>
> To run an R script using Rscript, I type
>    ./myRscript.r
> at the command line (less typing), whereas with batch mode, it has to be
>    R CMD BATCH myRscript.r
> (more typing) but if I want any R options applied, such as --no-restore or
> --no-save, I include them within the script when using Rscript, but have to
> put them on the command line outside the script when using BATCH.
>
> One can actually execute an R command at the shell prompt using Rscript,
> which can't be done with BATCH:
>
> [296]% Rscript -e 3+4
> [1] 7
> [298]% Rscript -e 'sqrt(2)'
> [1] 1.414214
>
> If I want to pass custom parameters to the script (script-specific
> parameters of my own that I put on the command line), the syntax for either
> supplying them or parsing them might be different. I'm not sure, since I
> don't do this very often, and never use CMD BATCH. But it would be worth
> checking.
>
> -Don
>
> --
> Don MacQueen
> Lawrence Livermore National Laboratory
> 7000 East Ave., L-627
> Livermore, CA 94550
> 925-423-1062
> Lab cell 925-724-7509
>
>
>
> On 7/25/18, 8:22 AM, "R-help on behalf of Rich Shepard" <
> r-help-bounces using r-project.org on behalf of rshepard using appl-ecosys.com> wrote:
>
>     On Wed, 25 Jul 2018, Bert Gunter wrote:
>
>     > "Within R one can use source() to run a batch file of R commands,
> while R
>     > CMD BATCH and Rscript are run from the command line. Is this
> correct?"
>     >
>     > Yes.
>
>     Bert,
>
>        Thanks for confirming.
>
>     > I think your query answers your query: You use Rscript when you want
> to use
>     > R in the command environment, perhaps as part of an analytical
> pipeline;
>     > and you source an R file when you want to work within R.
>
>        That's a given. Why would I prefer Rscript over R CMD BATCH, or
>     vice-versa? I did not see much difference between the two in their help
>     files.
>
>     Regards,
>
>     Rich
>
>     ______________________________________________
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>
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/
> posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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