How to change the cell color of a cell of an R Shiny data table dependent on it's value?

Question

I am attempting to change the cell color of cells of an R Shiny data table dependent on their value. As an example, I\'ve created the following app:

# ui.R

         


        

Answer 1

Here are two ideas:

I want all cells containing integers to be colored red

(1) Mark integers using Javascript:

library(DT)
df <- head(iris)
df %>% 
  datatable %>% 
  formatStyle(1:4, color = JS("value % 1 === 0 ? 'red' : ''"))

Selectively, I'd like to color only the cells at row 2 column 2 and row 5 column 1

(2) Mark cells using hidden value columns:

m <- matrix(F, ncol = ncol(df)-1, nrow = nrow(df))
m[rbind(c(2,2),c(5,1))] <- TRUE
df %>% 
  cbind(m) %>% 
  datatable(
    options=list(columnDefs = list(list(visible=FALSE, targets=1:4+ncol(df)))),
  ) %>% 
  formatStyle(
    columns = 1:4, 
    valueColumns = 1:4+ncol(df), 
    color = styleEqual(c(1,0), c("red", "black"))
  )

I'm abstracting from Shiny, since this seems to be a datatable question. Also, there may be better options.

Answer 2

This page has a bunch of tips for formatting DT data tables: https://rstudio.github.io/DT/010-style.html

For your specific question, there's the function formatStyle that allows you to set aesthetics based on specific values in the table:

library(DT)
options(DT.options = list(pageLength = 5))
df = as.data.frame(cbind(matrix(round(rnorm(50), 3), 10), sample(0:1, 10, TRUE)))

# style V6 based on values of V6
datatable(df) %>% formatStyle(
    'V6',
    backgroundColor = styleEqual(c(0, 1), c('gray', 'yellow'))
)

# style V1 based on values of V6
datatable(df) %>% formatStyle(
    'V1', 'V6',
    backgroundColor = styleEqual(c(0, 1), c('gray', 'yellow'))
)