Sweave: use a chunk as a latex command parameter

Question

Is it somehow possible with Sweave to define a Latex-command and pass the results from a chunk as parameter?

Basically I want to create something like in this example:

\newcommand{\myCommand} [1] {
    \begin{figure} 
      \begin{center}
        #1
      \end{center}
    \end{figure}
}

\myCommand{
   <<fig=TRUE, results=hide>>
      plot(1:10,1:10)
   @
}

Answer 1

The output of a plot chunk is an includegraphics command in resulting .tex file :

\includegraphics[width=\maxwidth]{figure/testPlot}

So your new command should work (with corrected syntax here) : when the chunk is evaluated, the includegraphics is wrote to the .tex file. After this step, the latex code is evaluated, with all your commands and options.

\documentclass{article}
\begin{document}
\newcommand{\myCommand} [1] {
    \begin{figure}[t] 
      \begin{center}
        #1
      \end{center}
    \end{figure}
}
\myCommand{
   <<testPlot>>=
      plot(1:10,1:10)
   @
}
\end{document}

UPDATE This solution works only with knitr :

Rscript -e "library(knitr);knit('myFile.Rnw')"

Or to produce a pdf :

Rscript -e "library(knitr);knit2pdf('myFile.Rnw')"

With Rstudio, please read this : Weaving .Rnw using rstudio