# Interface to R

Contents

R is a computer language widely used in statistics. It includes a huge library of statistical and graphical functions which can be called from APL. For example, you can call R to do linear and non-linear modelling, classical statistical tests, time-series analysis, classification, clustering and many other tasks.

You can call the R library through the COM interface. This only works under Windows

The two methods are described below.

## Using COM Server (Dyalog)

### Installation

Install R statistical environment from http://www.r-project.org

Install R package rcproxy from http://cran.rakanu.com/bin/windows/contrib/2.8/rscproxy_1.2-0.zip

Install DCOM Server from http://cran.r-project.org/contrib/extra/dcom/

### Sample APL Session

)load r2apl d:\r2apl saved Mon Apr 06 22:10:59 2009 rinit ⍝ initialize connection to R COM server )obs ⍝ new object R is created R +x←10?100 ⍝ random numbers in APL 14 76 46 54 22 5 68 94 39 52 'y'rput x ⍝ send them to R 1 rexec 'mean(y)' ⍝ calculate mean value in R 47 +/x÷⍴x ⍝ the same in APL 47 y←rget 'y' ⍝ get variable y from R to APL x≡y ⍝ compare with original x 1 y←?100 6⍴2*30 ⍝ generate another random set y←(+/y÷2*30)÷6 'y'rput y ⍝ put it in R rexec 'hist(y)' ⍝ call R function to plot histogram

And R windows with histogram plot pops up:

### Dyalog APL functions

#### rinit

Initialize APL connection to R COM Server.

∇ rinit [1] '#.R'⎕WC'OleClient' 'StatConnectorSrv.StatConnector' [2] #.R.Init('R') ∇

#### rexec

Execute R expression and possibly return the result to APL

∇ a←{r}rexec exp [1] ⍝ Execute R expression and possibly return the result [2] ⍝R: R expression ('char') [3] ⍝L: if 1, then return the result [4] ⍎(0=⎕NC'r')/'r←0' [5] a←⍬ [6] :If r [7] a←#.R.Evaluate(exp) [8] :Else [9] #.R.EvaluateNoReturn(exp) [10] :EndIf ∇

#### rput

Put APL array into R

∇ {m}rput a;x1 [1] ⍝ Put APL array into R [2] ⍝R-name of variable to export from APL [3] ⍝L-name of variable to create in R [4] ⍎(0=⎕NC'm')/'m←''x''' ⍝ Default name is x [5] m←,⊂m [6] a←,⊂a [7] #.R.SetSymbol(m,a) ⍝ put var a into R with name m ∇

#### rget

Get R variable (matrix or vector) to APL

∇ r←rget name;rho;Re;Im;⎕ML [1] ⍝ Get R variable (matrix or vector) to APL [2] ⍝R-name of variable to import ('char') [3] ⎕ML←3 [4] r←#.R.GetSymbol(name) ∇

### Get workspace here

You can download a copy of the workspace here

Author: AlexanderSkomorokhov 2009-04-06