R-in-LaTeX

Template for printing R code in LaTeX

Multiple packages allow formatting programming/markup languages code in LaTeX. Among them, one of the most widespread is listings. Unfortunately, it does not properly format the R code, what has generated many questions about how to deal with it and explanations about these problems:

• lstlisting R keywords
• How to nicely display R code with the LaTeX package 'listings'?
• Best use of LaTeX listings package for pretty printing R code
• Colour for R code chunk in listings package

Therefore, I would not recommend using listings to format R code in LaTeX. Further, when there is a better alternative: using Sweave in combination with the R library knitr. How to do it is explained here.

Next, I give a summary with the steps I currently followed:

1. In the LaTeX file, include the R code between <<>>= at the beginning and @ at the end (instead of \begin{listings} and \end{listings}), and save this file with the Sweave extension .Rnw. Right below \begin{document}, include \SweaveOpts{key1=value1, key2=value2,...,keyn=valuen}, with your desired default options for the R code, as for example, echo=TRUE, etc.
2. In R, execute:

```r
library(knitr)
Sweave2knitr("file.Rnw")
```  

applied to your file.

3. In the output file file-knitr.Rnw ensure that right below \begin{document} you has

<<include=FALSE, echo=FALSE>>
opts_chunk$set(key1=value1, key2=value2,...,keyn=valuen)
@

Now the default options for the R code blocks (or chunks) can be those that the library knitr understands, more than those which Sweave allows.

4. Open this file with RStudio. Open Tools > Global Options > Sweave and choose the option Weave Rnw files using: knitr (at least with RStudio Version 1.1.463 with Windows 10). Then, in the main window of RStudio execute Compile PDF.
5. Among the output files is the pdf, but also the intermediate TeX file, which one can customize, including R code colours, before applying to it pdflatex.

The other file in this repository is a LaTeX template with the essential TeX output of this process, with some explanatory comments added.