Format table output in R shiny based on user inputs

Question

I have a table being display in a shiny app. I want to format the tables based on the values and color it accordingly. I have seen the formattable area coloring where based on the range of the values it defines the breaks and then color gradients are generated which are applied to the table. What I want to do is allow the user to fill the min and max value and depending on it the values in the table will be colored. So if the values range from 1-20 and if the user inputs are 5 and 15 , values below 5 and above 15 shouldnt have any color gradients applied to them. Below is the code of how I am doing currently using formatable area formatting.

library(shiny)
library(shinyWidgets)
library(shinydashboard)
library(DT)

sidebar <- dashboardSidebar(
  sidebarMenu(id = "tab",
              menuItem("1", tabName = "1")
  )
)
body <-   ## Body content
  dashboardBody(box(width = 12,fluidRow(
    fluidRow(  column(
      width = 3,  textInput("text1", label = h5("Min"), value = "Enter min")),
      column(
        width = 3, textInput("text2", label = h5("Max"), value = "Enter max"))),
    DT::dataTableOutput("op")
  )))

ui <-   dashboardPage(dashboardHeader(title = "Scorecard"),
                      sidebar,
                      body)

# Define the server code
server <- function(input, output,session) {
  df <- data.frame(month = c("mazda 3", "mazda cx5", "mazda 6","mazda miata","honda civic","honda accord"),
                   april = c(.1,.2,.3,.3,.4,.5),
                   may = c(.3,.4,.5,.2,.1,.5),
                   june = c(.2,.1,.5,.1,.2,.3))

  brks <- reactive({ quantile(df$april, probs = seq(.05, .95, .05), na.rm = TRUE)})
  clrs <- reactive({ round(seq(255, 175, length.out = length(brks()) + 1), 0) %>%
  {paste0("rgb(",.,",", ., ",255 )")}})

  df_format<- reactive ({datatable(df,options = list(searching = FALSE,pageLength = 15, lengthChange = FALSE))%>%
           formatStyle(names(df),backgroundColor = styleInterval(brks(), clrs()))})

  output$op <-renderDataTable({
    df_format()
  })

}

shinyApp(ui = ui, server = server)

Answer 1

Here is your working code.

You must use that input minimal and maximal value as limits for your sequence (I just change it to range - is easier for user to put a range like that) Then you generate sequence - according your notation - brks() - in my case I use length.out of 10 but you can put as many breaks as you want or dynamically. Then generate on

number of colors - 1

and in the end in styleInterval() for background add limits of white - or any other color you want.

library(shiny)
library(shinyWidgets)
library(shinydashboard)
library(DT)

sidebar <- dashboardSidebar(
   sidebarMenu(id = "tab",
            menuItem("1", tabName = "1")
   )
)
body <-   ## Body content
   dashboardBody(box(width = 12,fluidRow(
      fluidRow(column(
                width = 3, 
                sliderInput("range_value", 
                            label = h3("Put a range value"), 
                            min = 0, 
                            max = 100, 
                            value = c(5, 15)
                            )
                    )
             ),
    DT::dataTableOutput("op")
)))

ui <-   dashboardPage(dashboardHeader(title = "Scorecard"),
                      sidebar,
                      body)

# Define the server code
server <- function(input, output,session) {
df <- data.frame(month = c("mazda 3", "mazda cx5", "mazda 6","mazda miata","honda 
                 civic","honda accord"),
                 april = c(9, 8, 11,14,16,1),
                 may = c(3,4,15,12,11, 19),
                 june = c(2,11,9,7,14,1))
brks <- reactive({
    seq(input$range_value[1], input$range_value[2], length.out = 10) 
})

clrs <- reactive({ round(seq(255, 175, length.out = length(brks()) - 1), 0) %>%
{paste0("rgb(",.,",", ., ",255)")}})

df_format<- reactive ({datatable(df,options = list(searching = FALSE, pageLength = 15, lengthChange = FALSE)) %>%
            formatStyle(names(df), 
                        backgroundColor = styleInterval(c(brks()), c('white', clrs() ,'white'))
                        )
    })

output$op <-renderDataTable({
    df_format()
  })
}

shinyApp(ui = ui, server = server)