Inserting new lines into kable headers

Question

Problem description:

I'm writing a document in rMarkdown and I need to format a table before producing a PDF. The issue is that I'm having trouble inserting a new line in my kable headers that have been added using the add_headers_above command.

Currently the text "Month (persons)" - which is the first header added with that command - appears as one line. I'd like to break that so that a new line is inserted between "Month" and "(persons)".

The motivation is simply to save horizontal page space so that I can fit two tables size by size on one A4 sheet.

My attempt at the fix

I've tried to include \n in the add_headers_above command:

[...] %>% add_header_above(c(" ", 'Month \n (persons)' = 1, "TTY \n (persons)" = 1, "TTY \n (% chg.)" = 1)) But that hasn't worked.

Reproducible example:

---
output: pdf_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
library(knitr)
library(kableExtra)
library(tibble)
```
```{r}
df <- tribble(~Location, ~Jan_Qrt, ~Jan_year, ~growth,
"New South Wales",  16000,  403300,       3.30,
"Victoria",        -21200,    134100,       3.50,
"Queensland",        2100,  100200,       3.20,
"South Australia",  19700,  117900,       5.00,
"Western Australia",   5300,   13200,     1.60,
"Tasmania",         -8900,   24300,     1.90,
"Northern Territory",    -400,    5700,    2.40,
"Australian Cap",     300,   -4300,    -3.10,
"Australia",         800,   10600,     4.80)

kable(df, format = 'latex', booktabs = T, align = 'r') %>%
  kable_styling(full_width = F, font_size = 8) %>%
  row_spec(row = 9, bold = TRUE) %>%
  add_header_above(c(" ", 'Month (persons)' = 1, "TTY (persons)" = 1, "TTY (% chg.)" = 1))

  ```

Hao · Accepted Answer · 2018-04-02T21:17:36.350

For now, you will have to write some raw latex code by yourself.

As the answer in https://tex.stackexchange.com/questions/2441/how-to-add-a-forced-line-break-inside-a-table-cell suggested, you can try to use the makecell package. To do that, you can load the latex package using kableExtra::usepackage_latex() and then hack it through setting escape = F in add_header_above.

usepackage_latex("makecell")
kable(df, format = 'latex', booktabs = T, align = 'r') %>%
  kable_styling(full_width = F, font_size = 8) %>%
  row_spec(row = 9, bold = TRUE) %>%
  add_header_above(c(" ",
                     '\\\\thead{Month\\\\\\\\(persons)}' = 1,
                     "\\\\thead{TTY\\\\\\\\(persons)}" = 1,
                     "\\\\thead{TTY\\\\\\\\(\\\\% chg.)}" = 1),
                   escape = F)

Update

Never mind the latex mess above, I made it work in the dev version of kableExtra. Now you just do

library(kableExtra)

mtcars[1:5, 1:5] %>%
  kable("latex", booktabs = T) %>%
  add_header_above(c(" ", "aa\na" = 2, "bbb" = 3))

Perfect. When is that version going to make its way into the production version of kableExtra? — Dom, Apr 02 '18 at 23:05
http://haozhu233.github.io/kableExtra/best_practice_for_newline_in_latex_table.pdf — Hao, Apr 03 '18 at 00:27

score 0 · Answer 2 · answered Apr 02 '18 at 15:35

This is going to be hard because LaTeX doesn't like newlines inside table cells - see e.g. https://tex.stackexchange.com/questions/2441/how-to-add-a-forced-line-break-inside-a-table-cell to get a sense of how hard this is. You are almost certainly better off just inserting a separate row for the "(persons)" et cetera.

score 0 · Answer 3 · answered May 11 '23 at 14:39

kable(df, format = 'latex', booktabs = T, align = 'r', 
      caption = "first line\\\\second line)

\\ would make a new line in LaTeX. However, kable will escape special characters, so this will not work directly. Therefore, we have to escape the escape.

Inserting new lines into kable headers

Problem description:

My attempt at the fix

Reproducible example:

3 Answers3