I'm generating a knitr (focusing on .Rmd files) manual for a project and wanted to embed a code chunk that actually displays the " ``` " marks as well as the internal chunk syntax. E.g.
``` {r sample, eval= FALSE}
Code example
```
So basically the exact visual you see above. Any thoughts on how to do this?
You can do this by using four spaces before your code as follows:
So this:
Becomes this:
There also is this SO-meta discussion on how to escape this backtick in Markdown
If you mean how to display the three backticks, the answer is "indent by 4 spaces" (see Pandoc's four-space rule)". If you mean how to display a literal knitr code chunk, the answer has been given by knitr FAQ #8.
Related
this is the closest question I have found to mine, but it looks a bit dated.
I want to add a code chunk with eval = FALSE into the footnote of an R Markdown html document. I have tried the standard notation as in 2.5.1 here, but knitting ignores it.
Thanks for your help.
It should work if it your footnote looks like this:
Random Numbers[^a-random-footnote-label]
Other text for your document.
Other text for your document.
Other text for your document.
[^a-random-footnote-label]:
```{r, echo = F}
runif(1:10)
```
So you don't define the footnote directly via Random Numbers^[content footnote]. Instead you name it and define the contents later.
This may seem like a basic question, but I can't seem to find an answer for this anywhere.
Is there a way to enter a comment between the brackets of the chunk in Rmarkdown.
For example:
```{r some comments}
plot(cars)
```
I tries various types of charecters such as ##, >,<> but they all still creted an error when I Knit the output to html.
The reason I want this is so that when I use RStudio I can collapse the chunks and have a comment there about what's in that chunk.
Thank you
Late to answer, but you can use , inside the brackets to separate parts and add a label (akin to a comment I would say):
``` {r, my-chunk, echo=FALSE, fig.height=4, dev='jpeg'}
```
Reference for more info: https://yihui.org/knitr/options/
I am working on a document about R software, which is currently stored in a Rnw file to eventually process it with Sweave. The document contains several R code chunks, of the usual form:
<<>>=
R Code
#
Next to some code lines, I would like to add specific comments, which I would like to be displayed like usual LaTeX text (so that they are easily recognizable as comments). Is there a way to display R code chunks and corresponding comments next to each other when using sweave or knitR?
Thank you for your help!
If you want the to be formatted like code (I assume that is what you mean) you can use the following code:
\begin{filecontents*}{my_r_code_test.r}
R code
#
|\includegraphics[width=0.5\textwidth]{example-image}|
\end{filecontents*}
\documentclass{article}
\usepackage{xcolor}
\usepackage{graphicx}
\usepackage{listings,mdframed}
\lstset{
language=R,
backgroundcolor=\color{black!5}, % set backgroundcolor
basicstyle=\footnotesize\ttfamily,% basic font setting
columns=fullflexible,
}
\begin{document}
\begin{mdframed}[backgroundcolor=black!5,linewidth=0pt,%
innerleftmargin=0pt,innertopmargin=0pt,innerbottommargin=0pt]
\lstinputlisting[escapeinside=||]{my_r_code_test.r}
\end{mdframed}
\end{document}
Which produces
at the top of the page.
Hope this helps!
In R, using knitr, is there a way to prevent line breaks in the HTML when results='hide' and echo=FALSE?
In this case:
First I do this,
```{r results='hide', echo=FALSE}
x=4;x
```
then I do that.
I get:
First I do this,
then I do that.
with both a break and an extra line between.
I'd like to get:
First I do this, then I do that.
instead.
Generally speaking, I'd like for code chunks to not insert new lines so that markdown is free to eat the one after the first line of text.
Thanks,
I assume you're creating an HTML document from an R Markdown document. In that case, you can use the inline R code capability offered by knitr by using the ` characters starting with the letter r.
Example:
In your R Markdown, write:
First I do this,`r x=4` then I do that. I can call x by doing `r x`.
And as output, you get:
First I do this, then I do that. I can call x by doing 4.
Note that in my example, I evaluated the variable x, but if you do not want to evaluate it, you do not have to. The variable x should still be assigned a value of 4 from the
`r x=4`
part of the R Markdown.
This is Inline R Code, and is documented here under the section "Inline R Code".
EDIT:
Note that Inline R Code has properties that are analogous to "echo=FALSE". And if you want to hide the results from inline R code, you can use base R functions to hide the output. See this question.
Try something like:
``` {r , results="asis", echo=F, eval=T}
if(showMe){
cat("printed")
} else {
cat("<!-- no break line -->")
}
```
I would like to make an R code chunk (in Sweave) printed inside a framed box in the resulting pdf.
Is there an easy solution for doing that?
The short answer is that yes, there is an easy way. Just add the following lines, or something like them to the preamble of your Sweave document:
\DefineVerbatimEnvironment{Sinput}{Verbatim} {xleftmargin=2em,
frame=single}
\DefineVerbatimEnvironment{Soutput}{Verbatim}{xleftmargin=2em,
frame=single}
This works because the appearance of code (and output) chunks is controlled by the definition of the Sinput and Soutput environments. These are both Verbatim environments as provided by the LaTeX package fancyvrb. (Click here for a 73 page pdf describing the numerous options that fancyvrb provides).
A quick look in the file Sweave.sty reveals the default definition of those two environments:
\DefineVerbatimEnvironment{Sinput}{Verbatim}{fontshape=sl}
\DefineVerbatimEnvironment{Soutput}{Verbatim}{}
\DefineVerbatimEnvironment{Scode}{Verbatim}{fontshape=sl}
To change those definitions, just add \DefineVerbatimEnvironment statements of your own devising either: (a) at the end of the Sweave.sty file; or (b) at the start of your *.Snw document.
Finally, here's an example to show what this looks like in practice:
\documentclass[a4paper]{article}
\usepackage{Sweave}
\DefineVerbatimEnvironment{Sinput}{Verbatim} {xleftmargin=2em,
frame=single}
\DefineVerbatimEnvironment{Soutput}{Verbatim}{xleftmargin=2em,
frame=single}
\title{Sweave with boxes}
\begin{document}
\maketitle
<<echo=FALSE>>=
options(width=60)
#
Here is an example of a code chunk followed by an output chunk,
both enclosed in boxes.
<<>>=
print(rnorm(99))
#
\end{document}
knitr, a successor of Sweave, by default outputs all echoed R code in boxes, and also formats it to the margins. Other nice features include syntax coloring and PGF integration.
Sweave code of average complexity needs only minor if any adaptions to run with knitr.