longtable + booktabs breaks on row starting with ( or [

[vincentarelbundock]

Apparently, when using both booktabs and longtable, if a row starts with the characters ( or [, latex compilation doesn't work. This happened to me when attempting to compile a notebook where a table had "(Intercept)" as a cell in the left-column.

This weird behavior is not caused by gt per se. One solution is documented here: https://tex.stackexchange.com/questions/228755/undefined-control-sequence-on-left-parenthesis-after-midrule-in-longtable/228756#228756

That is to use \midrule\relax instead of just \midrule.

I could probably hack around this ingtsummary, but this problem may arise for other gt users as well.

What do you think?

---

---
title: "R Notebook"
output: pdf_document
---

```{r}
library(gt)
data.frame('a' = c('OK', 'OK'), 'b' = 1:2) %>% gt()

data.frame('a' = c('(BAD)', 'OK'), 'b' = 1:2) %>% gt()

[rich-iannone]

I've tried out the code and indeed ran into the LaTeX error because the compiler thinks that ( or [ continues from \midrule. I tried to apply a fix by adding \relax after every \midrule but I ran into problems there as well. This will unfortunately require some more experimentation on my part to get to a solution.

[vincentarelbundock]

I'm curious to know what other issues you encountered. No pressure though, i know time is scarce. In modelsummary, I implemented a workaround function called knit_latex to use until things are fixed here. The second table compiles fine with \midrule\relax. I imagine the problem comes with more complicated examples.

library(gt)
library(gtsummary)

data.frame('a' = c('(BAD)', 'OK'), 'b' = 1:2) %>% gt() %>% as_latex() %>% cat
#> \captionsetup[table]{labelformat=empty,skip=1pt}
#> \begin{longtable}{cr}
#> \toprule
#> a & b \\ 
#> \midrule
#> (BAD) & 1 \\ 
#> OK & 2 \\ 
#> \bottomrule
#> \end{longtable}

data.frame('a' = c('(BAD)', 'OK'), 'b' = 1:2) %>% gt() %>% gtsummary::knit_latex() %>% cat
#> \captionsetup[table]{labelformat=empty,skip=1pt}
#> \begin{longtable}{cr}
#> \toprule
#> a & b \\ 
#> \midrule\relax
#> (BAD) & 1 \\ 
#> OK & 2 \\ 
#> \bottomrule
#> \end{longtable}

^{Created on 2019-01-31 by the reprex package (v0.2.1)}

[steveputman]

Let me know if this belongs in a separate issue, but I wonder if this bug is related (which is also not limited to gt): it's another \midrule issue appearing in longtable. When rows are grouped and the last group in the table has only one row, the \midrule before that last row gets dropped. This compiles, but the output obviously has a \midrule missing so the group label looks like a row.

library(tidyverse)
library(gt)

tribble(
  ~groupname, ~Subtype, ~Units,
  "Group1", "A", 100,
  "Group2", "B", 200) %>%
  gt() %>% 
  as_latex() %>% 
  cat
#> \captionsetup[table]{labelformat=empty,skip=1pt}
#> \begin{longtable}{lr}
#> \toprule
#> Subtype & Units \\ 
#> \midrule
#> \multicolumn{1}{l}{Group1} \\ 
#> \midrule
#> A & 100 \\ 
#> \midrule
#> \multicolumn{1}{l}{Group2} \\ 
#> B & 200 \\ 
#> \bottomrule
#> \end{longtable}

^{Created on 2019-02-05 by the reprex package (v0.2.1)}