R gt package -background coloring a single cell, when it equals a certain value

Question

I am using gt Package from github and would like to background-colorize all entries in a column of a table which equal the value "0". I found e.g. the following code in the Internet:

# Get a palette of 8 pastel colors from
# the RColorBrewer package
pal <- RColorBrewer::brewer.pal(8, "Pastel2")

# Create lighter and darker variants
# of the base palette (one step lower, one
# step higher)
pal_darker  <- pal %>% adjust_luminance(-1.0)
pal_lighter <- pal %>% adjust_luminance(+1.0)

# Create a tibble and make a gt table
# from it; color each column in order of
# increasingly darker palettes (with
# `data_color()`)
tab_1 <-
  dplyr::tibble(a = 1:8, b = 1:8, c = 1:8) %>%
  gt() %>%
  data_color(
    columns = vars(a),
    colors = scales::col_numeric(
      palette = pal_lighter,
      domain = c(1, 8)
    )
  ) %>%
  data_color(
    columns = vars(b),
    colors = scales::col_numeric(
      palette = pal,
      domain = c(1, 8)
    )
  ) %>%
  data_color(
    columns = vars(c),
    colors = scales::col_numeric(
      palette = pal_darker,
      domain = c(1, 8)
    )
  )

tab_1

But all of those solutions I found are about coloring a range of cells with a range of colors. Is it also possible with a single color on single cells based on a condition?

Thank you!

Answer 1

Since you do not provide the value of pal in your code, I have omitted it here. But the example shows coloring at the cell level, with a condition that the value of column c is greater than 3.

library(gt)
tab_1 <-
    dplyr::tibble(a = 1:8, b = 1:8, c = 1:8) %>%
    gt() %>%
    data_color(
        columns = vars(a),
        colors = scales::col_numeric(
            palette = c('red'),
            domain = c(1, 8)
        )
    ) %>%
    data_color(
        columns = vars(b),
        colors = scales::col_numeric(
            palette = 'green',
            domain = c(1, 8)
        )
    ) %>%
    tab_style(
        style = cell_fill(color = 'grey'),
        locations = cells_body(
        columns = vars(c), 
        rows = c > 3
    ))

tab_1