I'm editing an R markdown file (.Rmd) that has a lot of R code blocks to move groups of those code blocks into "child" documents to simplify rearranging sections (if nothing else). As I convert sections to child documents, I would like to test the new child document without running the rest of the blocks and other children. However, when I use to comment out those sections, the R blocks still run (but RStudio makes the sections "look" as though they were commented out).
If I eliminate the preceding and trailing "```"s (i.e., the code block signifiers), the commenting works fine. However, as I said, I've got lots of code blocks and something like would be more convenient.
So, how do I comment out the R code blocks so they won't run?
In RStudio, if you highlight from (at least) one row above an R code chunk to (at least) the last row of the R code chunk,1 and then type ctrl-shift-C (in OSX or Windows) or command-shift-C (OSX only), RStudio will place html comment tags on the chunk.
For example:
```{r cars}
summary(cars)
plot(pressure)
```
After highlighting this and type ctrl-shift-C, this becomes:
<!-- ```{r cars} -->
<!-- summary(cars) -->
<!-- plot(pressure) -->
<!-- ``` -->
To selectively comment out multiple chunks, you can use the RStudio find/replace tool with the regex option checked. It takes two replacement steps (it can probably be done in one step, but I'm not sure how to do a regex to capture across multiple lines in RStudio).
Step 1: Comment out the first line of one or more chunks:
Find: (```{r.*)
Replace: <!--\1
Step 2: Comment out the last line of one or more chunks:
Find: (```)$
Replace: \1-->
1 You must include the row above the chunk in the highlight. Otherwise, RStudio will place R comment tags (#) at the beginning of each row of the chunk and the commented lines will appear as plain text in the output document.
In an Rmarkdown document, we can apply certain options to each R code chunk that determines whether the code inside will be run, printed, show error messages, etc.
To have a specific code chunk not run, use:
```{r cars, eval=FALSE}
summary(cars)
```
To have a specific code chunk not run or print into the created doc, use:
```{r cars, eval=FALSE, echo=FALSE}
summary(cars)
```
"TRUE" is used for the opposite effects and is the default.
If you have many code chunks you need to comment out, you can take the suggestion from #eipi10 (thanks) and use find/replace with the regex option selected. So, the find would be "(```{r.*)", and the replace would be "\1, eval=FALSE, echo=FALSE}" (without the double quotes).
Related
I'm having a problem with assigning LaTeX environments within an RMarkdown for-loop code-chunk.
In short, I've written an R Markdown document and a series of R-scripts to automatically generate PDF reports at the end of a long data analysis pipeline. The main section of the report can have a variable number of sections that I'm generating using a for-loop, with each section containing a \subsection heading, a datatable and plot generated by ggplot. Some of these sections will be very long (spanning several pages) and some will be very short (~1/4 of a page).
At the moment I'm just inserting a \pagebreak at the end of each for-loop iteration, but that leaves a lot of wasted space with the shorter sections, so I'm trying to "group" each section (i.e. the heading, table and chart) so that there can be several per page, but they will break to a new page if the whole section won't fit.
I've tried using a figure or minipage environment, but for some reason those commands are printed as literal text when the plot is included; these work as expected with the heading and data table, but aren't returned properly in the presence of the image.
I've also tried to create a LaTeX samepage environment around the whole subsection (although not sure this will behave correctly with multi-page sections?) and then it appears that the Markdown generated for the plot is not interpreted correctly somewhere along the way (Pandoc?) when it's within that environment and throws an error when compiling the TeX due to the raw Markdown ![]... image tag.
Finally, I've also tried implementing \pagebreak[x] and \nopagebreak[y] hints at various points in the subsection but can't seem get these to be produce the desired page breaking behaviour.
I've generated an MWE that reproduces my issues below.
I'd be really grateful for any suggestions on how to get around this, or better ways of approaching "grouping" of elements that are generated in a dynamic fashion like this?
---
title: "Untitled"
author: "I don't know what I'm doing"
date: "26/07/2020"
output:
pdf_document:
latex_engine: xelatex
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = FALSE, dev = "cairo_pdf")
```
```{r cars, results='asis'}
for (i in 1:5){
cat("\\begin{figure}")
cat(paste0("\\subsection{This is subsection ",i,"}"))
cat("\\Huge Here's some bulk text that would represent a data table... kasvfkwsvg fiauwe grfiwgiu iudaldbau iausbd ouasbou asdbva asdbaisd i iuahihai hiuh iaiuhqijdblab ihlibljkb liuglugu h uhi uhi uhqw iuh qoijhoijoijoi qwegru wqe grouw egq\\newline")
plot(mtcars$wt,mtcars[,i])
cat("\\end{figure}")
}
```
Edit to add: interestingly these figure and minipage environments seems to work as expected when executing the same example in an .Rnw using knitr... so does that narrow it down to an issue with Pandoc? Again, any help much appreciated!
What happens is that the raw TeX commands are not treated as TeX when going through Markdown. You can fix that by explicitly marking the relevant snippets as LaTeX:
for (i in 1:5){
cat("`\\begin{figure}`{=latex}")
cat(paste0("\\subsection{This is subsection ",i,"}"))
cat("\\Huge Here's some bulk text that would represent a data table... kasvfkwsvg fiauwe grfiwgiu iudaldbau iausbd ouasbou asdbva asdbaisd i iuahihai hiuh iaiuhqijdblab ihlibljkb liuglugu h uhi uhi uhqw iuh qoijhoijoijoi qwegru wqe grouw egq\\newline")
plot(mtcars$wt,mtcars[,i])
cat("`\\end{figure}`{=latex}")
}
See the generic raw attribute section in the pandoc manual for details.
I'm writing a report in R Markdown in which I don't want to print any of my R code in the main body of the report – I just want to show plots, calculate variables that I substitute into the text inline, and sometimes show a small amount of raw R output. Therefore, I write something like this:
In the following plot, we see that blah blah blah:
```{r snippetName, echo=F}
plot(df$x, df$y)
```
Now...
That's all well and good. But I would also like to provide the R code at the end of the document for anybody curious to see how it was produced. Right now I have to manually write something like this:
Here is snippet 1, and a description of what section of the report
this belongs to and how it's used:
```{r snippetName, eval=F}
```
Here is snippet 2:
```{r snippetTwoName, eval=F}
```
<!-- and so on for 20+ snippets -->
This gets rather tedious and error-prone once there are more than a few code snippets. Is there any way I could loop over the snippets and print them out automatically? I'm hoping I could do something like:
```{r snippetName, echo=F, comment="This is snippet 1:"}
# the code for this snippet
```
and somehow substitute the following result into the document at a specified point when it's knitted:
This is snippet 1:
```{r snippetName, eval=F}
```
I suppose I could write some post-processing code to scan through the .Rmd file, find all the snippets, and pull out the code with a regex or something (I seem to remember there's some kind of options file you can use to inject commands into the pandoc process?), but I'm hoping there might be something simpler.
Edit: This is definitely not a duplicate – if you read my question thoroughly, the last code block shows me doing exactly what the answer to the linked question suggests (with a slight difference in syntax, which could have been the source of the confusion?). I'm looking for a way to not have to write out that last code block manually for all 20+ snippets in the document.
This is do-able within knitr, no need to use pandoc. Based on an example posted by Yihui at https://github.com/yihui/knitr-examples/blob/master/073-code-appendix.Rnw
Set echo=FALSE throughout your document: opts_chunk$set(echo = FALSE)
Then put this chunk at the end to print all code:
```{r show-code, ref.label=all_labels(), echo = TRUE, eval=FALSE}
```
This will print code for all chunks. Currently they all show up in a single block; I'd love to figure out how to put in the chunk label or some other header... For now I start my chunks with comments (probably not a bad idea in any case).
Updated: to show only the chunks that were evaluated, use:
ref.label = all_labels(!exists('engine')) - see question 40919201
Since this is quite difficult if not impossible to do with knitr, we can take advantage of the next step, the pandoc compilation, and of pandoc's ability to manipulate content with filters. So we write a normal Rmd document with echo=TRUE and the code chunks are printed as usual when they are called.
Then, we write a filter that finds every codeblock of language R (this is how a code chunk will be coded in pandoc), removes it from the document (replacing it, here, with an empty paragraph) and storing it in a list. We then add the list of all codeblocks at the end of the document. For this last step, the problem is that there really is no way to tell a python filter to add content at the end of a document (there might be a way in haskell, but I don't know it). So we need to add a placeholder at the end of the Rmd document to tell the filter to add the R code at this point. Here, I consider that the placeholder will be a CodeBlock with code lastchunk.
Here is the filter, which we could save as postpone_chunks.py.
#!/usr/bin/env python
from pandocfilters import toJSONFilter, Str, Para, CodeBlock
chunks = []
def postpone_chunks(key, value, format, meta):
if key == 'CodeBlock':
[[ident, classes, keyvals], code] = value
if "r" in classes:
chunks.append(CodeBlock([ident, classes, keyvals], code))
return Para([Str("")])
elif code == 'lastchunk':
return chunks
if __name__ == "__main__":
toJSONFilter(postpone_chunks)
Now, we can ask knitr to execute it with pandoc_args. Note that we need to remember to add the placeholder at the end of the document.
---
title: A test
output:
html_document:
pandoc_args: ["--filter", "postpone_chunks.py"]
---
Here is a plot.
```{r}
plot(iris)
```
Here is a table.
```{r}
table(iris$Species)
```
And here are the code chunks used to make them:
lastchunk
There is probably a better way to write this in haskell, where you won't need the placeholder. One could also customize the way the code chunks are returned at the end to add a title before each one for instance.
I am preparing a .Rmd document that begins with an executive summary. I would like to include some inline R code to present a few of the key results up front; however, those results are calculated as part of the body later in the document.
Is there any way to present a result in the rendered document out of order/sequence with the actual calculation?
You could use chunk reuse in knitr (see http://yihui.name/knitr/demo/reference/). Here you would put your chunks to analyze first but not create the output, then output the summary, then the details. Here is some quick markdown knitr code to show this:
```{r chunk1, echo=FALSE, results='hide'}
x <- rnorm(1)
x
```
the value of x is `r x`.
```{r chunk2, ref.label='chunk1', echo=TRUE, results='markup', eval=2}
```
Note that the code will be evaluated twice unless you take steps to prevent this (the eval=2 in my example).
Another option would be to create 2 child documents, the first runs your main code and creates the output, the second creates the summary. Then in your parent document you include the summary first, then the detail part. I think that you will need to run knitr on these by hand so that you do it in the correct order, the automatic child document tools would probably run in the wrong order.
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 -->")
}
```