kable caption can't handle % symbol knitting to pdf

[davidrjohnson4]

Describe the bug The LaTeX gets messed up (and the resulting pdf formatting is thrown off) when a % symbol is passed in a caption string to a kable object. And Rmd won't accept an escaped "%" as input when knitting.

To Reproduce Do the above ^.

# code to reproduce the bug.
kable(x = df, caption = '% of errors, by user group') %>% kable_styling()
...then knit to pdf.

[vincentarelbundock]

Did you try "escaping" the percent symbol using one or two backslashes?

[davidrjohnson4]

What I get is: escaping with a single \ doesn't work ("Error: '%' is an unrecognized escape in character string [...]"), but using \ results in "%" showing up in the table caption.

On Thu, Aug 4, 2022 at 7:39 AM Vincent Arel-Bundock < @.***> wrote:

Did you try "escaping" the percent symbol using one or two backslashes?

— Reply to this email directly, view it on GitHub https://github.com/haozhu233/kableExtra/issues/708#issuecomment-1205272853, or unsubscribe https://github.com/notifications/unsubscribe-auth/AU6PBKJ34C6NJTVKHPLIAQLVXPB2PANCNFSM5V4O56NQ . You are receiving this because you authored the thread.Message ID: @.***>

[vincentarelbundock]

OK, I believe your issue is a duplicate of https://github.com/haozhu233/kableExtra/issues/670

Try knitting this document:

---
output: pdf_document
---

```{r}
library(kableExtra)

kbl(mtcars[1:4, 1:4],
    caption = "\\% of errors, by user group.",
    escape = FALSE,
    format = "latex") |>
    kable_styling()
```

[vincentarelbundock]

I traced this back to an upstream problem in knitr. I opened an issue there: https://github.com/yihui/knitr/issues/2155

[vincentarelbundock]

The maintainer of knitr has replied in the Issue I linked to above. This problem will not be fixed upstream.

Since this would be a breaking change, and given kableExtra's mission of adding to knitr::kable, my sense is that the best way forward would be to just add a note in the documentation for the caption parameter, close this and related issues, and live with the knitr quirks.

It is pretty easy for users to escape the offending characters, as long as they know this is necessary.

What do you think @haozhu233?