selecting slider to display in r shinyapps - r

Question

I am trying to use selectInput in shiny aps to create a menu that changes the displayed slider.
ui <- fluidPage (
selectInput (inputId = "sat_act", "Choose your test:",
c("SAT" = "SATscore", "ACT" = "ACTscore")
sliderInput (inputId = "SATscore",
label = "Select your SAT score", step = 10,
value = 1000, min = 400, max = 1600),
sliderInput (inputId = "ACTscore",
label = "Select your ACT score",
value = 18, min = 1, max = 36)
plotOutput (outputId = "graph")
)
server <- function(input,output){}
shinyApp(ui = ui, server = server)
Currently, my code displays boy sliders and has no drop down menu. I am uncertain how to implement this and have not found an example online. Any help would be appreciated.

Answer 1

You could use renderUI().
On server side you evaluate your sat_act input and depending of the choice you render the new ui element:
output$score <- renderUI({
if(input$sat_act == "SATscore"){
return(...)
}
})
Full app:
library(shiny)
ui <- fluidPage (
selectInput (inputId = "sat_act", "Choose your test:",
c("SAT" = "SATscore", "ACT" = "ACTscore")),
uiOutput("score"),
plotOutput (outputId = "graph")
)
server <- function(input,output){
output$score <- renderUI({
if(input$sat_act == "SATscore"){
return(
sliderInput (inputId = "SATscore",
label = "Select your SAT score", step = 10,
value = 1000, min = 400, max = 1600)
)
}else{
return(
sliderInput (inputId = "ACTscore",
label = "Select your ACT score",
value = 18, min = 1, max = 36)
)
}
})
}
shinyApp(ui = ui, server = server)

Answer 2

Create an UI
library(shiny)
ui <- fluidPage (
selectInput(inputId = "sat_act", "Choose your test:",
c("SAT" = "SATscore", "ACT" = "ACTscore")),
uiOutput('slider'),
plotOutput (outputId = "graph")
)
server <- function(input,output){
output$slider = renderUI({
if (input$sat_act == 'SATscore') {
sliderInput(inputId = "SATscore",
label = "Select your SAT score", step = 10,
value = 1000, min = 400, max = 1600)
} else {
sliderInput(inputId = "ACTscore",
label = "Select your ACT score",
value = 18, min = 1, max = 36)
}
})
}
shinyApp(ui = ui, server = server)