Perl-R integration

[daverave]

I'm looking for an advice on how to integrate between perl and R (mostly in the direction of querying R or running R-like functions from within Perl).

Too often I find myself writing in Perl wishing I could now switch to R. What I usually end up doing is to write an R script that does what I like, then tell my Perl script to write down the data to a file and call the R script with this input file (simple system). The R scripts parses its input file, does some R magic and writes down the results into a file. The perl script then reads this new file, parses it and continues... not fun at all: a lot of parsing overhead, always need to keep the two in sync when changing anything, etc..

I've done some searching here and ran into some old posts mentioning RSPerl http://www.omegahat.org/RSPerl/index.html but it seems to have been last updated more than 3 years ago. I wonder if this is indeed the right choice, whether there any alternatives, and more generally - what do you commonly do when you need R?

Thanks!

[lima1]

Not exactly an answer to your question, but if I have to do some statistical analyses, I often use Perl just for data preparation. Mostly combining datasets from Spreadsheets and databases etc. Then I read and work with the data in R. I wrote Text::CSV::R for that.

If you need to switch back and forth between the languages, it's as you said still a PITA.

[Khen1950fx]

I like to use R::Writer.

[daverave]

I guess the simplest thing I'd like to do is to pass a Perl array to R as a vector. Can I do that using Writer?

[Khen1950fx]

I think that these examples of simple initialization will get you going. I hope they help.

To start:

#!/usr/bin/perl

use strict;
use warnings;
use R::Writer;

my $R = R::Writer->new();
$R->var(y => $R->expression( 'a * x ^ 2' ));
print $R->as_string(), "\n";

And a little more:

#!/usr/bin/perl

use strict;
use warnings;
use R::Writer;

my $R = R::Writer->new();
$R->var(x => $R->expression( 'a * x ^ 2' ));
$R->var(y => $R->expression( 'a * x ^ 2' ));
$R->call(c => \("x", "y"));
print $R->as_string(), "\n";