In bookdown how can I include R code within a custom block, whereby the R code will be parsed. Like in the example below the r code (plot function) will not be parsed. Is there a way to make this work?
```{block2 type='test'}
some text here
plot(1:10)
```
You can use text references as a hack. This seems to work as long as valid_markdown contains a single paragraph/line of markdown.
```{r}
valid_markdown <- your_function()
```
(ref:my_hack) `r valid_markdown`
```{block2, type="block"}
(ref:my_hack)
```
This hack works fine with text. Getting it work with plots will require a bit more work.
Related
I'm in the midst of writing a textbook. I frequently use custom code blocks to explain technical concepts. These are quite nice, but sometimes I want to embed an r chunk within a custom code block. As an example, I would like to do the following:
```{block, type="rmdnote"}
This is a very tricky concept to master. Let's look at a plot and output generated from R:
```{r, echo=FALSE}
plot(1:10, 1:10)
summary(1:10)
```
```
This will not work. Is there any way to embed an r chunk within a custom chunk?
I am using knit()and markdownToHTML() to automatically generate reports.
The issue is that I am not outputting plots when using these commands. However, when I use RStudio's Knit HTML button, the plots get generated. When I then use my own knit/markdown function, it suddenly outputs the plot. When I switch to another document and knit that one, the old plot appears.
Example:
```{r figA, result='asis', echo=TRUE, dpi=300, out.width="600px",
fig=TRUE, fig.align='center', fig.path="figure/"}
plot(1:10)
```
Using commands:
knit(rmd, md, quiet=TRUE)
markdownToHTML(md, html, stylesheet=style)
So I guess there are 2 questions, depending on how you want to approach it:
What magic is going on in Rstudio's Knit HTML?
How can I produce/include without depending on RStudio's Knit HTML button?
The only issue I see here is that this doesn't work when you have the chunk options {...} spanning two lines. If it's all on one line, it works fine. Am I missing something?
See how this is not allowed under knitr in the documentation:
Chunk options must be written in one line; no line breaks are allowed inside chunk options;
RStudio must handle linebreaks in a non-standard way.
This is really embarrassing, I really thought I read the documentation carefully:
include: (TRUE; logical) whether to include the chunk output in the
final output document; if include=FALSE, nothing will be written into
the output document, but the code is still evaluated and plot files
are generated if there are any plots in the chunk, so you can manually
insert figures; note this is the only chunk option that is not cached,
i.e., changing it will not invalidate the cache
Simply adding {..., include=TRUE} did the trick. I would say it would be a pretty sensible default though.
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 wish to use in line R code as part of a header in a r markdown file. However when i knit the file the fonts used on the header are different. How can I ensure the fonts are the same. A simple example is below.
`r 1+1` Header
-------------------------
You can wrap content in backticks to denote r code inline, as follows:
## Title `r 1+1` Header
Without a reproducible example it is hard to be precise, but one thing you might want to consider is to use the results="asis" chunk option in your R code so that the results are not wrapped in a code markup block. I am not sure how this works with inline commands, but you could use a regular R block and have it create the entire header from the R code, something like:
```r results="asis"
cat('# ', 1+1, " Header")
```
Sounds like it should be a common problem, but I didn't find an obvious trick.
Consider the knitr Rnw file below,
\documentclass[twocolumn, 12pt]{article}
\usepackage{graphicx}
\begin{document}
%\SweaveOpts{dev=pdf, fig.align=center}
\begin{figure*}
<<aaa, fig.width=8, fig.height=5, fig.show=hold>>=
plot(1,1)
#
\end{figure*}
\end{document}
I would like this wide figure to span two columns, using a {figure*} LaTeX environment. Is there a hook for that?
EDIT: wrapping the chunk in figure* gives the following output.
Two facts:
knitr makes everything accessible for you, so LaTeX tricks are often unnecessary;
there is a chunk hook with which you can wrap your chunk results;
A simple-minded solutions is:
knit_hooks$set(chunk = function(x, options) {
sprintf('\\begin{figure*}\n%s\n\\end{figure*}', x)
})
I leave the rest of work to you to take care of more details in options (e.g. when options$fig.keep == 'none', you should not wrap the output in figure*). You may want to see how the default chunk hook for LaTeX is defined in knitr to know better how the chunk hook works.
However, in this case, I tend to write the LaTeX code by myself in the document instead of automatically creating it. After you have got figure*, you may start to think about \caption{} and \label{} (not hard, but I still want to see them in LaTeX).
Not sure about how knitr but for Sweave (and basic latex) there is in fact a trick: have the R code produce a pdf file, and then use standard \includegraphics to pull it in.
So with this:
\documentclass[twocolumn, 12pt]{article}
\usepackage{graphicx}
\begin{document}
%\SweaveOpts{dev=pdf}
<<aaa,fig=FALSE,print=FALSE,echo=FALSE>>=
pdf("mychart.pdf", width=6, height=3)
set.seed(42)
plot(cumsum(rnorm(100)), type='l', main="yet another random walk")
invisible(dev.off())
#
\begin{figure*}
\includegraphics{mychart.pdf}
\end{figure*}
\end{document}
I got the document below (which I then converted from pdf to png):
I also had a similar problem while preparing a figure that should span two columns in a IEEE two-column conference paper.
Setting the chunk hook caused some strange error in my setup.
Even this simple hook: knit_hooks$set(chunk = function(x, options) x)
But after looking into knitr::opts_chunk$get(), I realized that simply setting fig.env="figure*" solves the problem in an elegant way.
Here is how my chunk looks like in an Rnw file:
<<fig1, fig.width=18, fig.height=6, fig.env="figure*">>=
#