KableExtra using row_spec in collapsed rows

Question

I have a dataset that is set up like the following mtcars summary:

mtcarssumm <- mtcars %>%
  group_by(cyl, gear) %>% 
  summarise(meanMPG = mean(mpg)) %>% 
  mutate(gear=as.character(gear)) %>% 
  bind_rows(group_by(mtcars,cyl) %>% 
  summarise(meanMPG=mean(mpg)) %>% 
  mutate(gear='Total')) %>% 
  arrange(cyl)

cyl gear  meanMPG
   <dbl> <chr>   <dbl>
 1     4 3        21.5
 2     4 4        26.9
 3     4 5        28.2
 4     4 Total    26.7
 5     6 3        19.8
 6     6 4        19.8
 7     6 5        19.7
 8     6 Total    19.7
 9     8 3        15.0
10     8 5        15.4
11     8 Total    15.1

What I would like is to create a table using kableextra, where the rows with gear = Total to be shaded. I'm currently using row_spec to do this. I'm also using collapse_rows to collapse down the repeated values in cyl:

mtcarssumm %>%
  kbl(booktabs = TRUE) %>% 
  collapse_rows(1, latex_hline = "major", valign = "middle") %>% 
  kable_styling() %>% 
  row_spec(which(mtcarssumm$gear == "Total"), background = "#e5e5e5")

When I convert to PDF, the entire row is shaded, as in the image below.

Is there a way to use collapse_rows and row_spec so the shading is only in the rows that are not collapsed? (Note, this code gives the desired result in HTML output but not in PDF output.

Thank you!

Answer 1

I figured out a fix - I changed the first column's background (the collapsed one)

mtcarssumm %>% 
  kbl(booktabs = TRUE) %>% 
  collapse_rows(1,latex_hline = "major", valign = "middle") %>% 
  kable_styling() %>% 
  row_spec(which(mtcarssumm$gear == "Total"), background = "#e5e5e5") %>%
  column_spec(1, background = "white")