Using output variable within selectInput of conditionaPanel

Is it possible to pass the output value from the server portion of a shiny app into a selectInput portion of a conditionalPanel? I'm trying the following, but it doesn't seem to be using the output value from output.items_list_selection in the switch statement to render what I'm after.

ui <- fluidPage(
           sidebarLayout(
            sidebarPanel(
             # the user can choose from two options within the radio buttons
             radioButtons("items_list_selection", label = "select item list"
                           , choices = list("Items - Item number & name" = "Both",  "Items - Item name only" = "Name"), selected = "Both")
             , conditionalPanel(
                  condition = "output.items_list_selection"
                  , selectInput("items", label = 'Select items'
                       # this is where I don't think I'm properly passing the value from output
                      , choices = switch( "output.items_list_selection", "Both" = items_names_id, "Name" = items_names)
                      , multiple = TRUE))

            # action button so the user can submit for analysis based on their selected options
            , actionButton("go", "Run", style = "color: white; background-color: #2759aa")
     )
  )

server <- function(input, output){
   
  output$items_list_selection <- reactive({
    input$items_list_selection
  })
  
  outputOptions(output, "items_list_selection", suspendWhenHidden = FALSE)  

}
  

Hi,

Your description was a bit confusing, but if it's the selectInput you'd like to update on the go, you can use the updateSelectInput function on the server side.

This is what I assumed your goal was:

library(shiny)

ui <- fluidPage(
    sidebarLayout(
        sidebarPanel(
            # the user can choose from two options within the radio buttons
            radioButtons("items_list_selection", label = "select item list"
                         , choices = list("Items - Item number & name" = "Both",  "Items - Item name only" = "Name"), selected = "Both")
            , selectInput("items", "Select items", choices = "")
            
            # action button so the user can submit for analysis based on their selected options
            , actionButton("go", "Run", style = "color: white; background-color: #2759aa")
        ), 
        mainPanel()
    )
)
    
server <- function(input, output, session){ #add session variable if updating UI
    
    observeEvent(input$items_list_selection, {
        #Here add code to filter options based on items_list_selection
        myChoices = paste(input$items_list_selection, "_option_", 1:5, sep = "")
        
        #Update the selectInput
        updateSelectInput(session, "items", choices = myChoices)
    })
    
    observeEvent(input$go, {
        #Button code goes here...
    })
    

}

shinyApp(ui, server)

Let me know if that's correct

Grtz,
PJ

Thank you very much for the reply and my apologies for the confusing explanation/description.

Your suggestion was something I had actually attempted at implementing beforehand. While it did exactly what I wanted, it did impede performance of the app quite a bit (most notably when switching between lists a user may selected in my Shiny app), hence I continued to explore other potential solutions.

What I was trying to explain in the original post is that conditionalPanel allows for certain UI rendering depending on whether a certain condition is met. In my original post, that condition was condition = "output.items_list_selection" which could take one of the two options "Both" or "Name". It seems that R/Shiny is able to use either of these two values and extract it from the "output.items_list_selection" string at this place in the code, however, just a few lines down in the switch statement, R/Shiny doesn't interepret "output.items_list_selection" as either one of "Both" or "Name", but literally as a string.

I imagined it would behave as it would when evaluated at the condition = level of the code, but it doesn't. If there was somehow I could perhaps extract the value held within "output.items_list_selection" to pass to the switch statement, that would be ideal. Hope this is a little more clear.

Hi,

I'm sorry it didn't work out as you liked. I think your approach is a bit convoluted as the conditional panel is made for something else than feeding into a switch function (which is an R function and is not going to work in the UI).

The only way I see it is creating two conditional panels, each with their own input, and displaying it depending on the choice of items_list_selection. Still,you'll need the updateSelectInput if you want to update the choices of the lists themselves on the go...

Give this a try:

library("shiny")

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      # the user can choose from two options within the radio buttons
      radioButtons("items_list_selection", label = "select item list"
                   , choices = list("Items - Item number & name" = "Both",  "Items - Item name only" = "Name"), selected = "Both")
      , conditionalPanel(
        condition = "output.items_list_selection == 'Both'"
        , selectInput("itemsBoth", label = 'Select items'
                      # this is where I don't think I'm properly passing the value from output
                      , choices = c("Both_Choice1", "Both_Choice2", "Both_Choice3")
                      , multiple = TRUE)), 
      conditionalPanel(
                        condition = "output.items_list_selection == 'Name'"
                        , selectInput("itemsName", label = 'Select items'
                                      # this is where I don't think I'm properly passing the value from output
                                      , choices = c("Name_Choice1", "Name_Choice2")
                                      , multiple = TRUE))
      
      # action button so the user can submit for analysis based on their selected options
      , actionButton("go", "Run", style = "color: white; background-color: #2759aa")
    ),
    mainPanel()
  )
  
)
  
  server <- function(input, output){
    
    output$items_list_selection <- reactive({
      input$items_list_selection
    })
    
    outputOptions(output, "items_list_selection", suspendWhenHidden = FALSE)  
    
}
  
shinyApp(ui, server)

It has the same result, and I'd be surprised if it were faster than my first suggestion, but since I still don't get your issue 100% it might help ...

Grtz
PJ