I would like to generate several copies of a question with randomly generated data in order to upload to Moodle and make a quiz. This question would include a table which depends on the data generated each time. How can this be done? I tried using xtable but it generates a table with no margins and format when uploaded to Moodle. I also tried ggpubr but it was not possible to include the table.
I read that one can generate a '.png', for example, and using 'include_supplement' and \includegraphics for .Rnw the file is imported into the file. This is useful when only one copy is generated because only one file would be the one imported. But what happens when multiple copies of the question with different data have to be created at once?
Any help would be appreciated.
Thank you.
Overview
Table formatting is not so straightforward for Moodle, both when starting from an exercise in R/LaTeX format (Rnw, as you do) or in R/Markdown format (Rmd). Below I'm showing a couple of variations of what you can do although I'm not 100% happy with all of them. In all cases the example is static but could be made dynamic in the "usual" way by inserting the random numbers into the respective tables. If you have problems with making one of the solutions dynamic, please let me know.
Plain
When you are starting in Rnw you typically generate a {tabular} object either by hand or via packages like xtable or knitr::kable etc. These are converted to valid HTML and imported into Moodle but the formatting with lines (horizontal and/or vertical) is not preserved. The same is true when starting in Rmd and using plain Markdown markup to code the table (again by hand or via knitr::kable etc.).
Example:
Rnw:
\begin{question}
Consider the following table:
\begin{tabular}{lrr}
\hline
Name & Min & Max \\
\hline
Foo & 0 & 1 \\
Bar & 0 & 100 \\
\hline
\end{tabular}
What is the overall maximum?
\end{question}
\exname{Table}
\extype{num}
\exsolution{100}
\extol{0.01}
Rmd: Would be similar to above but the table in plain Markdown as:
| Name | Min | Max |
|:-----|----:|----:|
| Foo | 0 | 1 |
| Bar | 0 | 100 |
Some other learning management systems (like OpenOLAT for example) offer suitable table classes in their CSS so that we can tweak the <table> in the resulting HTML to <table class="mytable"> (where the "mytable" class would need to be provided in the CSS). I looked around a bit in Moodle's question editor but there doesn't seem to be support for such dedicated CSS table styles. If anyone knows more about this I would appreciate some pointers.
HTML
The best alternative to this is probably to start in Rmd but instead of writing the table in Markdown you can use full HTML directly. This gives you extensive possibilities for styling the cells by hand. There are also various packages that help you with this. Below I'm using a combination of knitr::kable and kableExtra::kable_styling. The latter offers many more options than those that I use below.
Example:
Rmd:
Question
========
Consider the following table:
```{r, echo = FALSE, results = "asis"}
d <- data.frame(
Name = c("Foo", "Bar"),
Min = c(0, 1),
Max = c(0, 100)
)
kableExtra::kable_styling(
knitr::kable(d, format = "html", booktabs = TRUE),
bootstrap_options = "bordered", full_width = FALSE, position = "left")
```
What is the overall maximum?
Meta-information
================
exname: Table
extype: num
exsolution: 100
extol: 0.01
Rnw: I guess the same trick should be possible in Rnw exercises, i.e., include HTML in the LaTeX exercise and preserve that when converting to HTML with pandoc. However, I didn't manage to find the right flag for that. So this currently works just from Rmd exercises.
LaTeX
You can also typeset the table with LaTeX and use pdfLaTeX for rendering and then convert the output to PNG or SVG. This is supported by the tex2image() function in the exams package. This can be used in both Rnw and Rmd exercises and the resulting image has to be included in the exercise. The disadvantage is that the fonts etc. differ between the table and the main question (and you have to play with the fontsize and resolution in tex2image()). Moreover, this is relatively slow because pdfLaTeX has to be run on each exercise with such a table.
Example:
Rnw:
\begin{question}
Consider the following table:
<<echo=FALSE, results=hide>>=
tab <- '\\begin{tabular}{lrr}
\\hline
Name & Min & Max \\\\
\\hline
Foo & 0 & 1 \\\\
Bar & 0 & 100 \\\\
\\hline
\\end{tabular}'
tex2image(tab, name = "tab", dir = ".", pt = 8, resize = 250)
#
\includegraphics{tab.png}
What is the overall maximum?
\end{question}
\exname{Table}
\extype{num}
\exsolution{100}
\extol{0.01}
Rmd: The same code chunk generating the image could be used in Rmd. Just the \includegraphics would need to be replace by the corresponding ![]() Markdown.
CSS
Yet another option to render the table in Moodle is to insert a custom stylesheet with a class for the <table class="..."> to be rendered. A worked example is provided by Kenji Sato in his blog at: https://www.kenjisato.jp/en/post/2020/07/moodle-bordered-table/. We plan to integrate this with a couple of typical classes in exams2moodle() so that the CSS does not have to be inserted in every exercise manually. However, we did not yet get round to impelement this.
Sometimes we use quick and dirty hack.
$$
\begin{matrix}
\text{Name} & \text{Min} & \text{Max} \\
\ldots
\end{matrix}
$$
This hack has at least two advantages :)
It can be applied in a big team where everyone knows latex but only some guys know markdown.
It works both from .Rmd and .Rnw files. The plain \begin{tabular} way works only from .Rnw files.
Obvious con:
It's dirty!
I'm using VS Code to edit my markdown file, and need to make flowcharts (graph) to display workflow.
The problem is VS Code will not properly display the long text title, the last few part will be truncated as showed in follow:
```mermaid
graph LR
azzzzzzzz-->b
```
So I'm thinking of simply adding space after the text. However, I searched through the internet, and cannot find a way to type in multiple space.
```mermaid
graph LR
a[zzz z zzzz ]-->b
```
No matter what I try, the actual title will only display 1 space only. So if anyone can help either on truncate issue of VS Code or teach me how to type in multiple space.
I've been struggling with it for whole day, please help! Thanks a lot!
According to documentation Entity codes to escape characters you have to use the following:
It is possible to escape characters using the syntax examplified here.
graph LR
A["A double quote:#quot;"] -->B["A dec char:#9829;"]
In your example it could be the following:
```mermaid
graph LR
a["zzz #nbsp; z #nbsp; zzzz #nbsp; "]-->b
```
Back in the days GitHub Wiki supported embedding HTML tables, but now all our tables are not rendered anymore. Is support for HTML tables officially dropped (can't find corresponding news or blog post)?
GitHub does support table tag but it's not as extensible as in any HTML file. It's pretty much limited to what one may need for a wiki. In my view, it's pointless to use <table> because they are tiring compared to other markdowns that GitHub wiki use.
Markdown -
| First Header | Second Header |
| ------------- | ------------- |
| Content Cell | Content Cell |
| Content Cell | Content Cell |
Preview -
Equivalent HTML -
<table>
<tr><th>First Header</th><th>Second Header</th></tr>
<tr><td>Content Cell</td><td>Content Cell</td></tr>
<tr><td>Content Cell</td><td>Content Cell</td></tr>
</table>
PS. Here is a post on tables for markdown.
2017:
Back in the days GitHub Wiki supported embedding HTML tables, but now all our tables are not rendered anymore.
2022: they should be rendered now:
Updates to Markdown pasting on GitHub
May 19, 2022
We've made some updates to how paste formatting works in Markdown-enabled fields on GitHub.
For example, in code editors and on gists, you'll now be able to paste URLs on selected texts that will render as Markdown links like [...](https://...) by using the keyboard shortcut cmd|ctl + v..
The following paste formatting changes have been made to pull requests, issue comments and wikis:
Spreadsheet cells and HTML tables will render as Markdown tables
Any copied text containing links will render the links in Markdown.
All of this formatting can be disabled when pasting using the keyboard shortcut: cmd|ctl + shift + v or cmd|ctl + shift + Alt + v.
According to GitHub's Markdown spec, the Markdown parser permits most any raw HTML. The important thing is that the tags must begin at the start of the line. There are also rules which change the behavior when the raw block contains blank lines in some situations. Prior to adopting the current spec, I'm not sure if they were as strict about that, but that could be a reason for the change (some example input would help narrow down the possibilities).
And as another answer suggests, the GitHub Flavored Markdown spec includes a tables extension, so you can create tables natively in Markdown. This eliminates the need to structure your own HTML to the whims of the Markdown parser.
However, that is only the beginning of GitHub's processing of your input. After passing your input through the Markdown parser, there are four additional steps of processing taken on the output generated by Markdown as documented in the github/markup project. The most likely culprit is step two, which sanitizes the HTML. If your raw HTML doesn't match the expectations of the very narrow sanitizer, then it will get stripped out. The specifics of the santitizer are not documented, but the code is available to review and pretty easy to follow (even for those of use who aren't very familiar with Ruby).
Interestingly, the Markdown parser is sure to output HTML that the santitizer allows through, and in fact, tables are allowed. However, if you are using raw HTML rather than Markdown tables for more flexibility, then it is likely the extras that Markdown doesn't give you are causing the sanitizer to eat your tables (for example, you only get limited attributes, and improperly nests tags are stripped). In other words, raw HTML tables can only be limited to the basic features you already get with Markdown tables. Given the simplicity of Markdown tables over raw HTML, most people just use the markdown tables. YMMV.
I wish to show the knitR code in the final PDF together with its execution result.
I did not find yet a working way to fence "tripple-backticks"{r}..."tripple-backticks" blocks in the knitR code and see them as-is in the final PDF.
The backticks get interpreted whatever I do.
This is for tutorial purpose so that people see how to write knitR markdown. The use of html "pre" tags around the block of code leads to removal of the code.
for instance I wish to see this example fully first and then the result thereof
adding 4 spaces before each line like here does not work in RStudio and knit HTML fails
```{r test-haskell, engine='haskell', engine.path='ghc', cache=TRUE}
[x | x <- [1..10], odd x]
```
follow-up addition
I include here some RStudio Rmd code that leads to unexpected PDF content
in the pdf, the pre-code block simply disappeared.
The only fix I found is to invent a fake tag 'rmd' to fence the pieces of markdown I wish to keep as-is. I suspect this is a pandoc issue rather than knitr, unless there is a better way to fence code in knitr. The code I wish to keep can be any of bash, perl, R, or any other manguage used to process the data in the knitr tutorial.
my pandoc command was:
pandoc --variable=geometry:'top=1.5cm, bottom=1.5cm, left=2cm,
right=1cm' --variable=papersize:'a4paper' --number-sections
--table-of-contents --template=default.latex --highlight-style tango testrmd.md -o testrmd.pdf
Can it come from the template I used (default.latex)? It is the only template I found that meets my needs for vignette-like output. Same about 'tango' which is the only coloring scheme that shows some light background in code blocks.
As you see from the screenshots above I am a new-bee here (both in markdown and latex). Thanks for any help
After investigating, I've found mathjax can do this. But when I write some example in my markdown file, it doesn't show the correct equations:
I have added this in the head of markdown file:
<script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=default"></script>
And type the mathjax statement:
\(E=mc^2\)，$$x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2b}.$$
But github shows nothing for the math symbols! Please help me, thanks!
Tell me how to show math symbols in github markdown pages.
But github show nothing for the math symbols! please help me, thanks!
GitHub markdown parsing is performed by the SunDown (ex libUpSkirt) library.
The motto of the library is "Standards compliant, fast, secure markdown processing library in C". The important word being "secure" there, considering your question :).
Indeed, allowing javascript to be executed would be a bit off of the MarkDown standard text-to-HTML contract.
Moreover, everything that looks like a HTML tag is either escaped or stripped out.
Tell me how to show math symbols in general github markdown.
Your best bet would be to find a website similar to yuml.me which can generate on-the-fly images from by parsing the provided URL querystring.
Update
I've found some sites providing users with such service: codedogs.com (no longer seems to support embedding) or iTex2Img.
You may want to try them out. Of course, others may exist and some Google-fu will help you find them.
given the following markdown syntax
it will display the following image
Note: In order for the image to be properly displayed, you'll have to ensure the querystring part of the url is percent encoded. You can easily find online tools to help you with that task, such as www.url-encode-decode.com
Markdown supports inline HTML. Inline HTML can be used for both quick and simple inline equations and, with and external tool, more complex rendering.
Quick and Simple Inline
For quick and simple inline items use HTML ampersand entity codes. An example that combines this idea with subscript text in markdown is: hθ(x) = θo x + θ1x, the code for which follows.
h<sub>θ</sub>(x) = θ<sub>o</sub> x + θ<sub>1</sub>x
HTML ampersand entity codes for common math symbols can be found here. Codes for Greek letters here. An extensive list html entity codes to Unicode characters can be found here.
While this approach has limitations it works in practically all markdown and does not require any external libraries.
Complex Scalable Inline Rendering with LaTeX and Codecogs
If your needs are greater use an external LaTeX renderer like CodeCogs. Create an equation with CodeCogs editor. Choose svg for rendering and HTML for the embed code. Svg renders well on resize. HTML allows LaTeX to be easily read when you are looking at the source. Copy the embed code from the bottom of the page and paste it into your markdown.
<img src="https://latex.codecogs.com/svg.latex?\Large&space;x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}" title="\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}" />
Expressed in markdown becomes
This combines this answer and this answer.
GitHub support only somtimes worked using the above raw html syntax for readable LaTeX for me. If the above does not work for you another option is to instead choose URL Encoded rendering and use that output to manually create a link like:
This manually incorporates LaTex in the alt image text and uses an encoded URL for rendering on GitHub.
Multi-line Rendering
If you need multi-line rendering check out this answer.
It ’s 2020 now, let me summarize the progress of the mathematical formula rendering support of source code repository hosts.
GitHub & Bitbucket
GitHub and Bitbucket still do not support the rendering of mathematical formulas, whether it is the default delimiters or other.
Bitbucket Cloud / BCLOUD-11192 -- Add LaTeX Support in MarkDown Documents (BB-12552)
GitHub / markup -- Rendering math equations
GitHub / markup -- Support latex
GitHub Community Forum -- [FEATURE REQUEST] LaTeX Math in Markdown
talk.commonmark.org -- Can math formula added to the markdown
GitHub has hardly made any substantial progress in recent years.
GitLab
GitLab is already supported, but not the most common way. It uses its own delimiter.
This math is inline $`a^2+b^2=c^2`$.
This is on a separate line
```math
a^2+b^2=c^2
```
GitLab Flavored Markdown -- Math
Who supports the universal delimiters?
A Markdown parser used by Hugo
Other ways to render
Use web api to render according to A hack for showing LaTeX formulas in GitHub markdown, you can even write jupyter notebook.
readme2tex
It is officially supported since May 2022:
Render mathematical expressions in Markdown
You can now use LaTeX style syntax to render math expressions within Markdown inline (using $ delimiters) or in blocks (using $$ delimiters).
Writing expressions as blocks
To add math as a multiline block displayed separately from surrounding text, start a new line and delimit the expression with two dollar symbols $$.
**The Cauchy-Schwarz Inequality**
$$\left( \sum_{k=1}^n a_k b_k \right)^2 \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right)$$
Writing inline expressions
To include a math expression inline with your text, delimit the expression with a dollar symbol $.
This sentence uses `$` delimiters to show math inline: $\sqrt{3x-1}+(1+x)^2$
GitHub's math rendering capability uses MathJax; an open source, JavaScript-based display engine.
MathJax supports a wide range of LaTeX macros and a number of useful accessibility extensions.
For more information, see the MathJax documentation and the MathJax Accessibility Extensions documentation.
Some users have previously used a workaround to generate images of mathematical expressions through API requests.
Images generated this way will remain viewable, but this technique will no longer work.
Going forward, expressions should be written directly in Markdown using LaTeX syntax as described above.
For more information about authoring content with advanced formatting, see Working with advanced formatting in the GitHub documentation.
This is still beta, and criticised.
See "Math on GitHub: The Good, the Bad and the Ugly" from Nico Schlömer.
The syntax introduces:
Competing Markdown and math renderer
A math block hard to interpret
As noted by brc-dd in the comments:
June 2022:
Fenced block syntax for mathematical expressions
Users can now delineate mathematical expressions using ```math fenced code block syntax in addition to the already supported delimiters.
Two dollar sign $$ delimiters are not required if this method is used.
**Here is some math!**
```math
\sqrt{3}
.```
becomes:
Read more about working with advanced formatting.
Another possibility is to rely on GitHub's own notebook renderer. This even works right here in SO.
To render x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2b} use the following HTML img tag:
<img src="https://render.githubusercontent.com/render/math?math=x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2b}">
Live Demo:
What's great about this approach is that you can edit your formula directly in Markdown and the preview will update accordingly.
You can try it out by editing this answer. (Just throw away your edits if they don't add to the answer ;))
Source: https://gist.github.com/a-rodin/fef3f543412d6e1ec5b6cf55bf197d7b
One other work-around is to use jupyter notebooks and use the markdown mode in cells to render equations.
Basic stuff seems to work perfectly, like centered equations
\begin{equation}
...
\end{equation}
or inline equations
$ \sum_{\forall i}{x_i^{2}} $
Although, one of the functions that I really wanted did not render at all in github was \mbox{}, which was a bummer. But, all in all this has been the most successful way of rendering equations on github.
If just wanted to show math in the browser for yourself, you could try the Chrome extension GitHub with MathJax. It's quite convenient.
While GitHub won't interpret the MathJax formulas, you can automatically generate a new Markdown document with the formulae replaced by images.
I suggest you look at the GitHub app TeXify:
GitHub App that looks in your pushes for files with extension *.tex.md and renders it's TeX expressions as SVG images
How it works (from the source repository):
Whenever you push TeXify will run and seach for *.tex.md files in your last commit. For each one of those it'll run readme2tex which will take LaTeX expressions enclosed between dollar signs, convert it to plain SVG images, and then save the output into a .md extension file (That means that a file named README.tex.md will be processed and the output will be saved as README.md). After that, the output file and the new SVG images are then commited and pushed back to your repo.
I use the below mentioned process to convert equations to markdown. This works very well for me. Its very simple!!
Let's say, I want to represent matrix multiplication equation
Step 1:
Get the script for your formulae from here - https://csrgxtu.github.io/2015/03/20/Writing-Mathematic-Fomulars-in-Markdown/
My example: I wanted to represent Z(i,j)=X(i,k) * Y(k, j); k=1 to n into a summation formulae.
Referencing the website, the script needed was => Z_i_j=\sum_{k=1}^{10} X_i_k * Y_k_j
Step 2:
Use URL encoder - https://www.urlencoder.org/ to convert the script to a valid url
My example:
Step 3:
Use this website to generate the image by copy-pasting the output from Step 2 in the "eq" request parameter - http://www.sciweavers.org/tex2img.php?eq=<b><i>paste-output-here</i></b>&bc=White&fc=Black&im=jpg&fs=12&ff=arev&edit=
- My example:
http://www.sciweavers.org/tex2img.php?eq=Z_i_j=\sum_{k=1}^{10}%20X_i_k%20*%20Y_k_j&bc=White&fc=Black&im=jpg&fs=12&ff=arev&edit=
Step 4:
Reference image using markdown syntax - 
- Copy this in your markdown and you are good to go:
Image below is the output of markdown. Hurray!!
I just released a little Chrome extension, xhub, that lets you use LaTeX math (and more) in GitHub pages.
Pros:
You don't have to set up anything in your repo, just use math in your Markdown (sytax from GitLab):
Some display math:
```math
e^{i\pi} + 1 = 0
```
and some inline math, $`a^2 + b^2 = c^2`$.
It works on light and dark backgrounds alike.
You can copy-and-paste the math
Cons:
You have to install a browser extension once.
There is good solution for your problem - use TeXify github plugin (mentioned by Tom Hale answer - but I developed his answer in given link below) - more details about this github plugin and explanation why this is good approach you can find in that answer.
I used the following in the head of mark down file
<script type="text/javascript" async
src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.2/MathJax.js?
config=TeX-MML-AM_CHTML"
</script>
Then typed the following mathjax statement
$$x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2b}.$$
It worked for me
A "quick and dirty" solution is to maintain a standard .md file using standard TeX equations, e.g. _README.md.
When you are satisfied, pass the entire file through Pandoc to convert from standard Markdown to Markdown (Github flavour), and copy the output to README.md.
You can do this online for a quick turnaround, or install/configure Pandoc locally.
Mathcha is a sophisticated mathematics editor, but it can be used to render individual equations and save them as pure html, which you can then add to your documents as inline html OR you can save as SVG and insert as an image. https://www.mathcha.io/
You can embed your LaTeX in an image URL rendered by render.githubusercontent.com such as this one:
<img src="https://render.githubusercontent.com/render/math?math={x + y}">
which will render like this:
Which you'll notice is missing the + sign. To fix that you can URL encode the plus sigh as %2b or URL encode the entire equation, which will render like so:
Unfortunately this will always render in black, so you'll want to use this GitHub specific trick to render white text for users using dark mode and black text to users using light mode, by including the equation once with the #gh-light-mode-only and again with the LaTeX comand \color{white} and the #gh-dark-mode-only tag:
<img src="https://render.githubusercontent.com/render/math?math={x - y}#gh-light-mode-only">
<img src="https://render.githubusercontent.com/render/math?math={\color{white}x - y}#gh-dark-mode-only">
which will display this to light mode users:
and display this to dark mode users:
Now since May 2022, Github accept LATEX directly into Markdown, the only thing to do is to put the LATEX code inside $$$$ on your markdown
One more thing, you can colorize the math using the {\color{nameColor}text} on markdown
$${\color{red}\sum\limits_{\color{lightblue}i=0}^{\color{orange}n} {\color{pink}i}} = \frac{\color{pink}n!}{\color{lightblue}k!(n-k)!}$$
Example in a picture:
$$\sum\limits_{i=0}^n i^2$$ create the sum:
Regarding tex→image conversion, the tool LaTeXiT produces much higher quality output. I believe it is standard in most TeX distributions but you can certainly find it online if you don't already have it. All you need to do is put it in the TeX, drag the image to your desktop, then drag from your desktop to an image hosting site (I use imgur).
TeXify is no longer working. Check my repo readme2tex-action on how to create Github actions.
Add action.yml file to your repo at .github/workflows/action.yml.
Change branch main name if it is necessary.