Change renderTable title in shiny? - r

Question

I've managed build a simple shiny app that takes user input from a pre-defined list and passes this input as a vector to a function, then outputs the result of that function (here I've replaced that function with print).
library(shiny)
library(shinythemes)
server <- function(input, output) {
LIST_OF_STUFF = c("A", "B", "C", "D")
other_select <- function(inputId) {
reactive({
select_ids <- grep("^select_\\d+$", names(input), value = T)
other_select_ids <- setdiff(select_ids, inputId)
purrr::map(other_select_ids, purrr::partial(`[[`, input))
})
}
render_select <- function(i, label = "Enter selections") {
renderUI({
this_id <- paste0("select_", i)
this_input <- isolate(input[[this_id]])
selected_elsewhere <- unlist(other_select(this_id)())
available_choices <- setdiff(LIST_OF_STUFF, selected_elsewhere)
selectInput(inputId = this_id, label = label, choices = available_choices,
selected = this_input, multiple = TRUE)
})
}
output$select_1 <- render_select(1)
output$selected_var <- renderTable({
as.data.frame(print(input$select_1))
})
}
ui <- fluidPage(theme = "united",
titlePanel("Title"),
mainPanel(img(src = 'testimage.png', align = "right")),
uiOutput("select_1"),
tableOutput("selected_var"))
shinyApp(ui, server)
A few questions: The resulting table has the title "print(input$select_1)" -- how can I customize this?
I'd like to apply a theme to add some color to the app, but it doesn't seem to show up. How can I make the background or header bar colored?
The results table currently prints immediately upon user selection, but I'd like it to wait until the user is finished selecting input. How can I do this?
This is my first time using shiny or making any sort of interactive application, so forgive me if these are trivial questions. Thanks!

Answer 1

Data frame output
To display a custom name you could add a variable name to your data frame:
output$selected_var <- renderTable({
data.frame(selections = isolate(input$select_1))
})
App customization
Since it's a web app, you can customize (almost) any element of your app. You just have to target the elements that you want to modify, for example if you want to modify the color of the background and the color of the header, you can add custom CSS within your code:
tags$head(
tags$style(
HTML("h2 {
color: red;
}
body {
background-color: grey;
}")
)
)
Delay
To wait for the user to finish the selection, I would suggest you to add an actionButton that the user will have to press to render the table. One way to do this is to use an observeEvent and to isolate the input selection.
All in all
All in all, you could have an app that looks like this:
library(shiny)
library(shinythemes)
server <- function(input, output) {
LIST_OF_STUFF = c("A", "B", "C", "D")
other_select <- function(inputId) {
reactive({
select_ids <- grep("^select_\\d+$", names(input), value = T)
other_select_ids <- setdiff(select_ids, inputId)
purrr::map(other_select_ids, purrr::partial(`[[`, input))
})
}
render_select <- function(i, label = "Enter selections") {
renderUI({
this_id <- paste0("select_", i)
this_input <- isolate(input[[this_id]])
selected_elsewhere <- unlist(other_select(this_id)())
available_choices <- setdiff(LIST_OF_STUFF, selected_elsewhere)
selectInput(inputId = this_id, label = label, choices = available_choices,
selected = this_input, multiple = TRUE)
})
}
output$select_1 <- render_select(1)
observeEvent(input$run, {
output$selected_var <- renderTable({
data.frame(selections = isolate(input$select_1))
})
})
}
ui <- fluidPage(theme = "united",
titlePanel("Title"),
tags$head(
tags$style(
HTML("h2 {
color: red;
}
body {
background-color: grey;
}")
)
),
mainPanel(img(src = 'testimage.png', align = "right")),
uiOutput("select_1"),
actionButton("run", "Run"),
tableOutput("selected_var"))
shinyApp(ui, server)