How to create R markdown with empty code chunk? - r

How can I add an empty code chunk in R markdown? I have found several options to manipulate the html to give more white space. But I would like to present some empty lines in the well known gray code box in order to indicate space for assigments.
---
title: "Untitled"
author: "Author"
output: html_document
---
## R Markdown
```{r cars}
summary(cars)
```
## Homework
Please calculate the mean of the `speed` variable in `cars`.
```{r}
```

A hacky way... almost there:
```{r, code="'\n\n\n\n'", results=F}
```
A possible solution using results = 'asis' and relying on chunck HTML class:
```{r, results='asis', echo=F}
cat(
'<pre class="r">
<code class = "hlsj"> <span class="hljs-string"> <br> <br> </span> </code>
</pre>
')
```
Just add <br> to increase the number of lines.

There does not seem to be a way to get knitr to recognise a completely empty chunk as a chunk. It will always omit it, regardless of the chunk options.
You have to insert something to get it to render, for example a comment. So you can put the empty lines between two comments:
---
output: html_document
---
## Homework
Please calculate the mean of the `speed` variable in `cars`.
```{r}
# Insert code here
# End
```
Or with the strip.white=FALSE chunk option we can use a single comment line, but strangely this only works for leading, not trailing, whitespace:
---
output: html_document
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(strip.white = FALSE)
```
## Homework
Please calculate the mean of the `speed` variable in `cars`.
```{r}
# Insert code above
```

Related

Undesired PDF format from particular R Markdown YAML configuration

In R Studio, my R Markdown document begins like this:
---
title: 'ST 412: Homework 3'
author: "Camden White"
documentclass: amsart
geometry: margin=1in
output: pdf_document
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
## 1. Read Data Set and Define Variables
```{r, message=FALSE, warning=FALSE}
library(tidyverse)
library(magrittr)
```
When I do not include documentclass: amsart, everything works fine, but when I do include it, the library section is placed before the ## 1. Read Data Set and Define Variables header.
When there is text between the two components, the order is the same order in the code, but without it, the library section comes first. This does not happen with the default article document class, and I do not know why this occurs. How can I use the amsart document class and fix this ordering issue?
The problem seems to be that a subsection in amsart is basically what a paragraph is in normal classes: an unnumbered bold piece of text without an new paragraph after it. The text will just continue in the same line. As the grey box with the source code spans a whole line, it can't be placed there and shows up above. You can reproduce this with normal article class like this:
\documentclass{article}
\usepackage{framed}
\begin{document}
\paragraph{1. Read Data Set and Define}
\begin{framed}
test
\end{framed}
\end{document}
You can avoid the problem by making sure the source code isn't the first text in the subsection, e.g. by adding something invisible:
---
title: 'ST 412: Homework 3'
author: "Camden White"
documentclass: amsart
geometry: margin=1in
output: pdf_document
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
## 1. Read Data Set and Define Variables
\mbox{}
```{r, message=FALSE, warning=FALSE}
library(tidyverse)
library(magrittr)
```

RMarkdown suppress automatic figure numbering to html

Is there a way to suppress automatic figure numbering made by rmarkdown? The first plot rendered by R is the second figure, it added a Figure 1: prefix which is not what I need. I see a solution for PDF output but not html output.
Best,
Shixiang
It's difficult to know what you are looking for without a minimal reproducible example. But maybe you are looking for bookdown::html_document2 output.
Try the following:
---
title: "Example Document"
author: "Your name here"
output:
bookdown::html_document2
---
```{r cars, fig.cap = "plot"} # Figure with caption
plot(cars)
```
```{r cars3, fig.cap = ""} # Figure without caption
plot(cars)
```
This is the output of the above:

How can I automate different spacing between text and code blocks in R Markdown?

Consider the following R Markdown document:
---
title: "Stack Overflow Question"
author: "duckmayr"
date: "6/21/2019"
output: pdf_document
header-includes:
- \usepackage{setspace}
- \doublespacing
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
Here is some example text.
I want all the body text to be double-spaced,
but I want all echoed code from code chunks to be single spaced.
In other words, not this:
```{r}
## This code is double-spaced.
## I want it to be single spaced.
## How can I do that?
```
Is there a canned or relatively painless way to have all normal text double-spaced, but have all code echoed from code chunks single spaced? I tried consulting the guide to chunk options here, but couldn't quite find what I was looking for.
If you are outputting to pdf the most painless way might be adding some LaTeX commands to your Rmd document:
---
title: "Stack Overflow Question"
author: "duckmayr"
date: "6/21/2019"
output: pdf_document
header-includes:
- \usepackage{setspace}
- \doublespacing
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
Here is some example text. I want all the body text to be double-spaced, but I
want all echoed code from code chunks to be single spaced. In other words, not
this:
\singlespacing
```{r}
## This code is double-spaced.
## I want it to be single spaced.
## How can I do that?
```
\doublespacing
Some additional body text. Nor hence hoped her after other known defer his.
For county now sister engage had season better had waited. Occasional mrs
interested far expression acceptance. Day either mrs talent pulled men
rather regret admire but. Life ye sake it shed. Five lady he cold in meet up.
Alternatively, you could define a new chunk option using knitr chunk hooks. For instance, you could include in the setup chunk:
```{r setup, include=FALSE}
hook_chunk = knitr::knit_hooks$get('chunk')
knitr::knit_hooks$set(chunk = function(x, options) {
regular_output = hook_chunk(x, options)
# add latex commands if chunk option singlespacing is TRUE
if (isTRUE(options$singlespacing))
sprintf("\\singlespacing\n %s \n\\doublespacing", regular_output)
else
regular_output
})
knitr::opts_chunk$set(echo = TRUE, singlespacing = TRUE)
```
Some useful references:
Hooks - Customizable functions to run before/after a code chunk, tweak the output, and manipulate chunk options
How to Create New Chunk Options in R Markdown

Code in Columns in RMarkdown presentation

Often when I include r code in a rmarkdown pdf presentation, I want to use the space of the whole slide and therefore want to present the code and the output side-by-side.
In pure LaTex I would go for \begin{columns}...\end{columns} and then include the code/output manually using lstlistings or some other code-highlighting library. But that proves tedious if I exceed a couple of code examples.
Now I want to use RMarkdown for the presentations and would like to achieve a similar result.
However, the following code throws an error:
## This is slide 1
\begin{columns}[t]
\begin{column}{0.5\textwidth}
```{r, eval=F}
plot(1:10)
```
\end{column}
\begin{column}{0.5\textwidth}
```{r, echo=F}
plot(1:10)
```
\end{column}
\end{columns}
Leaving out the knitr code-chunks and replacing them with text works.
I am aware that it has something to do with the pandoc engine (see here), but wanted to ask if anybody has found a way around this issue.
Well, I may should have looked with a wider focus.
Here is a solution that works for Python, but can easily be adapted to Rmarkdown: https://stackoverflow.com/a/26069751/3048453
I ended up with this code:
in header.tex
\newcommand{\columnsbegin}{\begin{columns}}
\newcommand{\columnsend}{\end{columns}}
in presentation.Rmd
---
title: "Two-column codes in RMarkdown"
author: "My Name"
date: "February 4, 2017"
output:
beamer_presentation:
includes:
in_header: header.tex
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
## Testslide with Columns
\columnsbegin
\column{.5\textwidth}
```{r, eval=F}
plot(mtcars[, 1:3])
```
\column{.5\textwidth}
```{r, echo=F}
plot(mtcars[, 1:3])
```
\columnsend
Which results in this

R markdown Page Breaks from Function

I am trying to break to a new page from a R markdown document that is calling a function to produce a set of graphics for each set of data (400+ pages in some cases). I am using LaTeX.
Any ideas? Here is a simple example that demonstrates some my challenge though it doesn't use a function to produce the output.
---
title: "Test Page Break"
output: pdf_document
---
```{r}
summary(cars)
cat("\\pagebreak")
print(cars)
```
Update #1:
My example didn't demostrate the use of a function within the code chunk. Here is a better example.
---
title: "Test Page Break"
output: pdf_document
---
```{r}
pr_w_pagebreak <- function() {
print(summary(cars))
cat("\\pagebreak")
print(cars)
}
pr_w_pagebreak()
```
The trouble you'll have with your chunks is that you want some results to appear as 'markup' and some to appear 'asis'. If you want to get the page break with the single block as you have it, you will need to do:
```{r, echo=-2}
summary(cars)
knitr::asis_output("\\pagebreak")
print(cars)
```
Otherwise, you'll have to do
```{r}
summary(cars)
```
\pagebreak
```{r}
print(cars)
```
And as Floo0 points out, you can get LaTeX code from the R chunks if you use results = 'asis', but you have to be careful because the following will not give you what you want.
```{r, results='asis'}
summary(cars)
cat("\\pagebreak")
print(cars)
````

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