Coloring R input and output differently using knitr
I would like my R input code to be printed / displayed on a light gray background and the output on a white background. For example, if my .Rnw file contains this snippet:
<<>>=
t.test(zinc~sex, data = zinc.df)
@
I would like the input to appear on a light gray background:
> t.test (zinc ~ gender, data = zinc.df)
and the output to be displayed on a white background like
Welch Two Sample T-Test
data: zinc by gender
t = -15.08, df = 2678, p-value <2.2e-16
(The output is intentionally truncated, but you get the idea.) It looks like I could do it with newbie themes, but I can't see it. Like many others, I'm not going to start the game with a listing package.
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This is the best I can do:
\documentclass[12pt,letterpaper,twoside]{book}
\usepackage{inconsolata}
\usepackage{listings,color}
<<setup, include=FALSE>>=
options(width=60)
opts_chunk$set(fig.align='center', concordance=TRUE, fig.show='hold', size='footnotesize', prompt=FALSE, comment=NA, tidy=TRUE, results='markup', tidy.opts=list(width.cutoff=50), comment='#-#', highlight=TRUE)
opts_knit$set(concordance=TRUE,self.contained=FALSE)
color_block_output = function(x) {
function(x, options) paste('\\begin{outputblock}',x,'\\end{outputblock}',sep="")
}
knit_hooks$set(output = color_block_output(''))
@
\lstnewenvironment{outputblock}{
\lstset{backgroundcolor=\color{white},
frame=single,
framerule=0pt,
basicstyle=\ttfamily,
columns=fullflexible}}{}
\begin{document}
<<test>>=
print('test')
(mat <- matrix(data=1:25,nrow=5,ncol=5))
@
\end{document}
The result will be: 
I have not found a solution for a situation where there is no output (white space looks a bit weird) and trailing gray space. Anyway, this is a start, hope it helps.
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Your problem is best suited with a package listings
, but it shouldn't be painful - here's an example (take a look at backgroundcolor
parm's lstdefinestyle
):
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{listings}
\usepackage{color}
%-- Define your colors, easy to look up
\definecolor{Rcodegreen}{rgb}{0,0.6,0}
\definecolor{Rcodegray}{rgb}{0.5,0.5,0.5}
\definecolor{Rcodepurple}{rgb}{0.58,0,0.82}
\definecolor{Rbackcolour}{rgb}{0.95,0.95,0.92}
\lstdefinestyle{customstyle}{
backgroundcolor=\color{Rbackcolour},
commentstyle=\color{Rcodegreen},
keywordstyle=\color{Rmagenta},
numberstyle=\tiny\color{Rcodegray},
stringstyle=\color{Rcodepurple},
basicstyle=\footnotesize,
breakatwhitespace=false,
breaklines=true,
captionpos=b,
keepspaces=true,
numbers=left,
numbersep=5pt,
showspaces=false,
showstringspaces=false,
showtabs=false,
tabsize=2
}
\lstset{style=customstyle}
\title{Fooing with foo}
\begin{document}
\maketitle
<<tidy=TRUE,highlight=FALSE>>=
x <- "h3ll0 w0rld"
cat(x, "\n")
@
\end{document}
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If you only work with Rnw and Latex, you can use the background
chunks option . However, you will need to write your piece twice.
(1) c echo=TRUE
, eval=FALSE
andbackground='white'
<<echo=TRUE, eval=FALSE, background='white'>>=
@
(2) c echo=FALSE
, eval=TRUE
andbackground='yellow'
<<echo=FALSE, eval=TRUE, background='yellow'>>=
@
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