CODEWITHSUNDEEP
javar
marc esher
marc esher

Reputation: 4921

How do you run an R program from Java?

I have program written with R. I can run it from the R GUI and it spits out results.

Is there a way to run that program from Java?

Upvotes: 3

Views: 8373

Answers (3)

Steves
Steves

Reputation: 3234

You can also use FastR, which is R engine implemented on top of JVM. Using it from Java is as simple as:

Context context = Context.newBuilder("R").allowAllAccess(true).build();
int result = context.eval("R", "sum").execute(new int[] {3,4,5}).asInt();
context.eval("R", "print('you can eval any R code here');");

This is an example of how to pass data from Java to R and make it look like a data.frame. This is another example of how to redirect R graphics into Java Graphics2D object.

A more detailed description is in this article: https://medium.com/graalvm/faster-r-with-fastr-4b8db0e0dceb

and on the GraalVM website: http://graalvm.org

Upvotes: 1

Volokh
Volokh

Reputation: 390

I think one of the easiest possibilities to execute R code from some other environment is REST webservice.

For instance if you have an R-Script called example.R with the following function:

#* @get /hello
hello <- function() {
  print("hello")
}

You can run the following:

library(plumber)
r <- plumb("example.R")
r$run(port=8080)

If you then call the page 

http://localhost:8080/hello

your R code will be executed.

If you want to execute it from Java the solution could be:

   URL url = new URL("http://localhost:8080/hello");
   URLConnection connection = url.openConnection();
   BufferedReader br = new BufferedReader(new InputStreamReader( (connection.getInputStream())));
   String result = br.readLine();

Upvotes: 2

Ryan Guest
Ryan Guest

Reputation: 6470

You might want to take a look at these three projects.

Upvotes: 7

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