Calling R functions from Clojure
R, and the many incredibly useful packages that have been developed for it, provides a rich environment to do statistical computing. To access any of this, however, we'll need to be able to call functions from Clojure. We do this by constructing R expressions as strings, sending them to the R server, and getting the results back. The Rserve Java library helps us convert the results to Java objects that we can access.
Getting ready
We must first complete the recipe, Setting up R to talk to Clojure, and have Rserve running. We must also have the Clojure-specific parts of that recipe done and the connection to Rserve made.
How to do it…
Once we have a connection to Rserver, we can call functions by passing the complete call—function and arguments—to the server as a string and evaluating it. Then, we have to pull the results back out, as follows:
user=> (map #(.asDouble %)
(.. *r-cxn* (eval "qr(c(1,2,3,4,5,6,7))") asList))
(-11.832159566199232 1.0 1...
