How to get a plot generated by R returned in an output cell?

Question

It seems we'll never have built in two axis plots and list plots in Mathematica but you can make them in R.

Needs["RLink`"]
InstallR[];
REvaluate["{
 x <- 1:5
 y1 <- rnorm(5)
 y2 <- rnorm(5,20)
 par(mar=c(5,4,4,5)+.1)
 plot(x,y1,type=\"l\",col=\"red\")
 par(new=TRUE)
 plot(x,y2,,type=\"l\",col=\"blue\",xaxt=\"n\",yaxt=\"n\",xlab=\"\",\ ylab=\"\")
 axis(4)
 mtext(\"y2\",side=4,line=3)
 legend(\"topleft\",col=c(\"red\",\"blue\"),lty=1,legend=c(\"y1\",\"\
y2\"))}"]

Which returns this plot in a popup window:

How can I get the plot that is generated from this code to appear in an Output cell?

Answer 1

Wolfram website What's New? has quite a few cool examples of new features. We are interested here in

Using Higher-Order Functions and Closures to Structure Code: Flexible Plotting Routines

I will give it here to apply to your specific code.

"This example illustrates some means of code composition supported by RLink, which allow smooth and productive combined R-Mathematica workflows. Load RLink."

Needs["RLink`"]
InstallR[]

"The following creates a generic R wrapper that creates the plot and saves it to a file, and defines certain parameters for the resulting image."

mathematicaRPlotWrapper = RFunction["function(filename, plotfun){
     pdf(filename)
     plotfun()
     dev.off()
     }"];

"Create a Mathematica counterpart wrapper that automates file import and adds error-checking."

Clear[getRPlot];
getRPlot[plotFun_RFunction] := 
  With[{tempfile = FileNameJoin[{$TemporaryDirectory, "temp.pdf"}]}, 
   If[FileExistsQ[tempfile], DeleteFile[tempfile]];
   mathematicaRPlotWrapper[tempfile, plotFun];
   If[! FileExistsQ[tempfile], Return[$Failed]];
   Import[tempfile]];

Now, the above functions worked with all examples I tried. So I will apply it to your specific case here:

Show[#, ImageSize -> Medium, PlotRange -> All] &@
 getRPlot[RFunction["function(){
     x <- 1:5
    y1 <- rnorm(5)
    y2 <- rnorm(5,20)
    par(mar=c(5,4,4,5)+.1)
    plot(x,y1,type=\"l\",col=\"red\")
    par(new=TRUE)
    plot(x,y2,,type=\"l\",col=\"blue\",xaxt=\"n\",yaxt=\"n\",xlab=\"\"\
,\ ylab=\"\")
    axis(4)
    mtext(\"y2\",side=4,line=3)
    legend(\"topleft\",col=c(\"red\",\"blue\"),lty=1,legend=c(\"y1\",\
\"y2\"))
      }"]]