tables printed via kable(): double negative signs -- are transformed into symbol endash (–), being barely differentiable from -. Why/How can I force a representation of --?

[Gewerd-Strauss]

Description

Hello,

I am a bit confused, and I do not know how this happens.

Take the repo at https://github.com/Gewerd-Strauss/quarto-cli-10384 for a reprex.

The function create_Experiments_instructions_df() will create a dataframe; which can get printed to the console, with an example:

> df <- create_Experiments_instructions_DF(variants, repeats, parameter, unit, "degrees off of normal", "n","Variants/Filenames")
> df
  degrees off of normal [°]  n    Variants/Filenames
1                        -10  7 y-axis-tilt-gfa--10-1
2                         NA NA y-axis-tilt-gfa--10-2
3                         NA NA y-axis-tilt-gfa--10-3
4                         NA NA y-axis-tilt-gfa--10-4
5                         NA NA y-axis-tilt-gfa--10-5
6                         NA NA y-axis-tilt-gfa--10-6
7                         NA NA y-axis-tilt-gfa--10-7
8                         -5  7  y-axis-tilt-gfa--5-1
9                         NA NA  y-axis-tilt-gfa--5-2
10                        NA NA  y-axis-tilt-gfa--5-3
11                        NA NA  y-axis-tilt-gfa--5-4
12                        NA NA  y-axis-tilt-gfa--5-5
13                        NA NA  y-axis-tilt-gfa--5-6
14                        NA NA  y-axis-tilt-gfa--5-7
15                         0  7   y-axis-tilt-gfa-0-1
16                        NA NA   y-axis-tilt-gfa-0-2
17                        NA NA   y-axis-tilt-gfa-0-3
18                        NA NA   y-axis-tilt-gfa-0-4
19                        NA NA   y-axis-tilt-gfa-0-5
20                        NA NA   y-axis-tilt-gfa-0-6
21                        NA NA   y-axis-tilt-gfa-0-7
22                         5  7   y-axis-tilt-gfa-5-1
23                        NA NA   y-axis-tilt-gfa-5-2
24                        NA NA   y-axis-tilt-gfa-5-3
25                        NA NA   y-axis-tilt-gfa-5-4
26                        NA NA   y-axis-tilt-gfa-5-5
27                        NA NA   y-axis-tilt-gfa-5-6
28                        NA NA   y-axis-tilt-gfa-5-7
29                        10  7  y-axis-tilt-gfa-10-1
30                        NA NA  y-axis-tilt-gfa-10-2
31                        NA NA  y-axis-tilt-gfa-10-3
32                        NA NA  y-axis-tilt-gfa-10-4
33                        NA NA  y-axis-tilt-gfa-10-5
34                        NA NA  y-axis-tilt-gfa-10-6
35                        NA NA  y-axis-tilt-gfa-10-7

You notice that the column Variants/Filenames contains contains a strict format, and this format does consider negative values
y-axis-tilt-gfa--5-7 vs y-axis-tilt-gfa-5-1.

Unfortunately, if I render this to html, I get this table:

Notice that the dash before the 5 in the first row, and the dash before the 5 in the last row are different. It seems this is the only difference.
This is bad, because this table lies out how to name replicates. And they are not named by me, because I am remote and not performing them myself.

This will most definitely cause issues when names appear to map to two replicates of two completely different variants.

So the question is how I can force -- to render as --, instead of –

For direct comparison:

–
-

I am currently on 1.5.54

Any suggestions on how to resolve this issue?

Thank you.
Sincerely,
~Gw

[cderv]

This is again another occurence of the smart extension. It is already discussed for other use case

• Don't convert ascii to unicode in URLs #10042 (comment)
• Certain urls get mangled when rendering with python kernel #10021 (comment)

In your situation, this is probably because kable() will output Markdown table, and then Markdown is parsed by Pandoc with this extension activated which will conside -- as en-dashes.

The way you create the table right now is not protected against any markdown parsing. If you had y-axis-tilt-gfa-5-*1* for example the *1*, the output would have <em> for emphasize, as * means someting in Markdown.

So you need to account for that when you have special content in your table. Some solution

• Opting out smart extension, but this will apply to all your document.
• Consider using HTML tables as output - tools like kableExtra, gt or flextable are good solution
• Use knitr::kable() but set the format to html in the argument to write a HTML table. Cell in HTML table won't be parsed as markdown.

You could also use Markdown table, but process your data for visualization by escaping any character in your columns data that should escape for all markdown processing. Same things that is need sometimes for HTML tables, or LaTeX tables with special character.

In Quarto know that we parse HTML table, so output HTML tables is usually a good solution
https://quarto.org/docs/authoring/tables.html#html-tables

Hope it helps

[Gewerd-Strauss]

Thank you for the explanation of what was going on. I ended up experimenting with the various solutions, but didn't choose either for various reasons. In the end I just decided to escape the second minus (which belongs to the number, e.g. -5 via paste0("\\-", abs(x))).