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/
Related
I think the question is quite self-explanatory but for avoidance of doubt I'll explain with more detail below:
I have an R Markdown document that works well if converted to HTML or uploaded to GitHub. When converting to PDF (using Latex), the results are not so pretty. I find that the biggest problem in a Latex PDF document are line breaks. I can fix the line breaks issue on the PDF document by adding "\ " characters, but that throws my HTML document out of whack too.
Is there a way to manually add line breaks (or "space before/after paragraphs") for the PDF output only?
Thank you!
You can redefine the relevant spacings in the YAML header. \parskip controls the paragraph spacing. Code blocks are shaded using a snugshade environment from the framed package. We can also redefine the shaded environment for code blocks to have some vertical space at the start. Here's a reproducible example. Note: I also added the keep_tex parameter so you can see exactly what the generated tex file looks like, in case this is useful:
title: "test"
author: "A.N. Other"
header-includes:
- \setlength{\parskip}{\baselineskip}
- \renewenvironment{Shaded}{\vspace{\parskip}\begin{snugshade}}{\end{snugshade}}
output:
pdf_document:
keep_tex: true
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
## R Markdown
This is an R Markdown document. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see <http://rmarkdown.rstudio.com>.
When you click the **Knit** button a document will be generated that includes both content as well as the output of any embedded R code chunks within the document. You can embed an R code chunk like this:
```{r cars}
summary(cars)
```
## Including Plots
You can also embed plots, for example:
```{r pressure, echo=FALSE}
plot(pressure)
```
Note that the `echo = FALSE` parameter was added to the code chunk to prevent printing of the R code that generated the plot.
Once you output to HTML, you can just print the HTML webpage as PDF. that might be an easy way keep the original format
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.
I am producing a latex report which produces multiple plots in a dlply call. The dlply call is of course in a single chunk and in order to get labels and captions to change I am using a snippet from Steve Powell below. The approach works but it seems knitr doesnt quite format the output correctly. A simple example that demonstrates:
\documentclass{article}
\begin{document}
<startup,echo=FALSE,results='hide',message=FALSE,tidy=FALSE,warning=FALSE,fig.keep='all',comment=NA>>=
require(knitr)
require(ggplot2)
opts_knit$set(progress = F, verbose = F)
opts_chunk$set(comment=NA,
tidy=FALSE,
warning=FALSE,
message=FALSE,
echo=FALSE,
dpi=600,
fig.width=6.75, fig.height=4, # Default figure widths
dev=c("pdf",'tiff'),
dev.args=list(pdf=list(NULL),tiff=list(compression='lzw')),
error=FALSE)
#
<<plotloop,results='asis'>>=
for(x in seq(1,20)){
x1<-data.frame(x=seq(1,10),y=seq(1,10))
plt<-ggplot(data=x1,aes(x,y))+geom_point()
figLabel=paste('Figure',x,sep='')
capt<-paste('Caption for fig.',x)
cat(knit(text=(paste("<<",figLabel,",fig.pos='ht',fig.cap='",capt,"'>>=\nplt\n#",sep=''))))
}
#
\end{document}
This almost works. The trouble is that knitr places the closing \caption brace outside the \label brace which can be seen in the snippet from the .tex file below:
\begin{knitrout}
\definecolor{shadecolor}{rgb}{0.969, 0.969, 0.969}
\color{fgcolor}
\begin{figure}[ht]
\includegraphics[width=\maxwidth]{figure/Figure1} \caption[Caption for fig]{Caption for fig. 1\label{fig:Figure1}}
\end{figure}
\end{knitrout}
latex can handle this if there are only a few figures like this but with larger numbers of plots, it starts to place them incorrectly.
I have also tried this with a
fig.cap=paste('testLoop',seq(1,20))
approach and get the same result.
Further clarification: I found this on wikipedia's Latex/Floats... page:
If you want to label a figure so that you can reference it later, you have to add the label after the caption (inside seems to work in LaTeX 2e) but inside the floating environment. If it is declared outside, it will give the section number.
The 'inside seems to work in LaTeX 2e' part caught my attention. It seems it works only because the error is ignored a number of times? I am using
LaTeX2e <2005/12/01>.
I think the bit of code is in hook_plot_tex function line 120 of hooks-latex.R:
fig2 = sprintf('\\caption%s{%s\\label{%s}}\n\\end{%s}\n', scap, cap,
paste(lab, if (mcap) fig.cur, sep = ''), options$fig.env)
This would fix it?
fig2 = sprintf('\\caption%s{%s}\\label{%s}\n\\end{%s}\n', scap, cap,
paste(lab, if (mcap) fig.cur, sep = ''), options$fig.env)
Suggestions? I am not familiar with the github process...
Thanks!
Short answer is it seems to be a LaTeX issue caused by too many \includegraphics commands and no pagebreaks. Function to accomplish multiple figures with captions and labels from within loop (with credit to Steve Powell and Yihui):
plot.knit<-function(chunkLabel,#text for chunk label which is also used for figure file name
capt,#text for caption
plt)#plot object to be placed
{
cat(knit(text=(paste("<<",chunkLabel,",fig.pos='h',fig.cap='",capt,"'>>=\nplt\n#",sep=''))))
}
cat('\\newpage')#some sort of page break must be inserted along the way to keep latex from breaking.
This can be modified to add any of chunk options you would like.
Long Answer:
Here is what I did to get it to work. I downloaded knitr from github, made the suggested alteration above, compiled, and ran example. The altered code did not change the outcome. Further investigation of latex error took me to the LaTeX FAQ where it states:
The error also occurs in a long sequence of float environments, with no intervening text. Unless the environments will fit “here” (and you’ve allowed them to go “here”), there will never be a page break, and so there will never be an opportunity for LaTeX to reconsider placement. (Of course, the floats can’t all fit “here” if the sequence is sufficiently prolonged: once the page fills, LaTeX won’t place any more floats, leading to the error.
Techniques for resolution may involve redefining the floats using the float package’s [H] float qualifier, but you are unlikely to get away without using \clearpage from time to time.
So, I added
cat('\\clearpage')
after the plots are generated in each step of the loop. This resulted in no errors being thrown and the figures in correct locations. Also,
cat('\\newpage')
works and seems to do a better job at placing the figures 2 on a page in my actual document.
The working code:
\documentclass{article}
\begin{document}
<<startup,echo=FALSE,results='hide',message=FALSE,tidy=FALSE,warning=FALSE,fig.keep='all',comment=NA>>=
require(knitr)
require(ggplot2)
opts_knit$set(progress = F, verbose = F)
opts_chunk$set(comment=NA,
tidy=FALSE,
warning=FALSE,
message=FALSE,
echo=FALSE,
dpi=600,
fig.width=6.75, fig.height=4, # Default figure widths
dev=c("pdf",'tiff'),
dev.args=list(pdf=list(NULL),tiff=list(compression='lzw')),
error=FALSE)
#
<<plotloop,results='asis'>>=
for(x in seq(1,20)){
x1<-data.frame(x=seq(1,10),y=seq(1,10))
plt<-ggplot(data=x1,aes(x,y))+geom_point()
figLabel=paste('Figure',x,sep='')
capt<-paste('Caption for fig.',x)
cat(knit(text=(paste("<<",figLabel,",fig.pos='h',fig.cap='",capt,"'>>=\nplt\n#",sep=''))))
cat('\\newpage')
}
#
\end{document}
For documentary purposes, I want some code for a plot in the html-output, but not the plot. Later, I have to call the plotting code, and add something to the plot, but only seeing the additional code. I tried this:
```{r non.finished.plotting, eval=FALSE}
plot(1,type="n")
```
Some explanatory text here in the output:
"This produces an empty plot, and we could now add some points to it manually."
```{r add.layer, fig.width=5, fig.height=5}
<<non.finished.plotting, echo=FALSE>>
points(x=rnorm(100,1,0.1), y=rnorm(100,0.8,0.1) )
```
I have found the echo-notation at Yihui's, but when I knit this, I get an error message in the output.
## Error: plot.new has not been called yet
I also tried fiddling with the chunk options, but I could not find a combination which does what I want.
(Sorry, this is very basic, but I did not find something quite like this example.)
Chunk references in <<>> do not respect chunk options, so <<non.finished.plotting, echo=FALSE>> will not work. What you can do is to move the chunk option echo back to the main chunk like this:
```{r add.layer, fig.width=5, fig.height=5, echo=-1}
<<non.finished.plotting>>
points(x=rnorm(100,1,0.1), y=rnorm(100,0.8,0.1) )
```
echo=-1 means do not echo the first expression (as documented). This is probably what you want:
I'm writing an Rmd file, to be processed by knitr into HTML. It contains some R chunks that generate figures, which get stored as data URIs in HTML.
1) How do I add a caption to such an image? I'd like to have a caption that says something like "Figure 3: blah blah blah", where the "3" is automatically generated.
2) How do I later on reference this image, i.e., "as you can see in Figure 3, blah blah".
I'm late to the party, but I wanted to mention a small package I recently built to do figure captioning and cross-referencing with knitr. It is called kfigr and you can install it using devtools::install_github('mkoohafkan/kfigr'). It is still in active development but the main functionality is there. Be sure to check out the vignette, it shows some usage examples and defines some hooks for figure captions and anchors (I may later choose to have the package import knitr and define those hooks on load).
EDIT: kfigr is now available on CRAN!
You can create the figure numbers with a simple counter in R; see one example here. The problem is whether the markdown renderer will render the figure caption for you: R Markdown v1 won't, but v2 (based on Pandoc) will.
I do not know. There is no direct way to insert a label as an identifier for figures, so it is probably not possible to cross reference figures with pure Markdown. Once you've got issues like this, think (1) do I really need it? (2) if it is intended to be a document with a complicated structure, I think it is better to use LaTeX directly (Rnw documents).
Also very late to the party I changed Yihuis suggestion here that he also linked above to do referencing.
```{r functions, include=FALSE}
# A function for captioning and referencing images
fig <- local({
i <- 0
ref <- list()
list(
cap=function(refName, text) {
i <<- i + 1
ref[[refName]] <<- i
paste("Figure ", i, ": ", text, sep="")
},
ref=function(refName) {
ref[[refName]]
})
})
```
```{r cars, echo=FALSE, fig.cap=fig$cap("cars", "Here you see some interesting stuff about cars and such.")}
plot(cars)
```
What you always wanted to know about cars is shown in figure `r fig$ref("cars")`
One way to do both of these is described here: http://rmflight.github.io/posts/2012/10/papersinRmd.html
Another is described here (but I don't know if it does your #2). http://gforge.se/2014/01/fast-track-publishing-using-knitr-part-iii/
Another solution:
https://github.com/adletaw/captioner
From the README:
captioner() returns a captioner function for each set of figures, tables, etc. that you want to create. See the help files for more details.
For example:
> fig_nums <- captioner()
> fig_nums("my_pretty_figure", "my pretty figure's caption")
"Figure 1: my pretty figure's caption"
> fig_nums("my_pretty_figure", cite = TRUE)
I did both (figure numbers + references) with bookdown. I added in output section in the header of the file:
output:
bookdown::html_document2:
fig_caption : TRUE
Then I created a figure in a R code chunk like follows:
{r, my-fig-label,echo=F, eval=T, fig.align = 'center', fig.cap="This is my caption"}
knitr::include_graphics(here::here("images", "my_image.png"))
This produces an automatic number under your figure. You can refer to it with \#ref(fig:my-fig-label).
Using the official bookdown documentation 4.10 Numbered figure captions:
---
output: bookdown::html_document2
---
```{r cars, fig.cap = "An amazing plot"}
plot(cars)
```
```{r mtcars, fig.cap = "Another amazing plot"}
plot(mpg ~ hp, mtcars)
```