Set background color if one cell's (of multiple columns) content is specific string using gt package

Question

With code below (from this link), we can set background colors for the cells of multiple columns based on string contents using gt package:

library(gt)
library(tidyverse)

id <- c(1,2,3,4,5)
res1 <- c("true", "true", "false", "true", "false")
res2 <- c("false", NA, NA, "true", "true")
df <- data.frame(id, res1, res2)

df %>% 
  gt() %>% 
  data_color(
    columns = c("res1", "res2"),
    colors = c("green", "red"),
    apply_to = "fill",
    autocolor_text = FALSE)

Out:

Now let's say I will need to set red background color only if content is true for columns res1 and res2, if it's other values such as false or NA, just keep as original, which means I hope to highlight true cells for these two columns. How could I do that? Thanks.

References:

https://gt.rstudio.com/reference/tab_style.html

Answer 1

Using gt::tab_style you could do:

library(gt)
library(magrittr)

df %>% 
  gt() %>% 
  tab_style(
    style = list(
      cell_fill(color = "red")
    ),
    locations = cells_body(
      columns = c(res1, res2),
      rows = res1 == "true" & res2 == "true"
    )
  )

EDIT In case of multiple columns you could basically create the conditions like so. Basic idea it to first create a string containing the condition on which rows to target and using !!rlang::parse_expr to evaluate that string inside gt::cell_body:

Note: I added two more columns to your df to make the example more realistic.

library(gt)
library(magrittr)

df <- data.frame(id, res1, res2, res3 = res1, res4 = res2)


cols <- paste0("res", 1:4)
conditions <- lapply(cols, function(x) "true")
names(conditions) <- cols 

rows <- paste(glue::glue("{.col} == '{.value}'", .col = names(conditions), .value = conditions), collapse = " & ")

df %>%
  gt() %>%
  tab_style(
    style = list(
      cell_fill(color = "red")
    ),
    locations = cells_body(
      columns = all_of(cols),
      rows = !!rlang::parse_expr(rows)
    )
  )