thothal thothal - 3 days ago 5
R Question

Update sliderInput in Shiny reactively

I am trying to change the values from a

sliderInput
dynamically. The difficulty now is that I want to change from a
sliderInput
with one value, to a
sliderInput
with a range, which seems not to work.

The first actionbutton in the code below works, while the second does not what it is intended to do.

Is the only possibility to switch to an
uiOutput
element?

Code

library(shiny)
app <- shinyApp(
ui = bootstrapPage(
sliderInput("sld1", min = 0, max = 10, label = "y1", value = 5),
actionButton("acb1", "Change Value"),
actionButton("acb2", "Change Value to Range")
),
server = function(input, output, session) {
observeEvent(input$acb1, {
updateSliderInput(session, "sld1", value = 2)
})
observeEvent(input$acb2, {
updateSliderInput(session, "sld1", value = 2:7)
})
})
runApp(app)

Answer

You can maybe add the slider dynamically using renderUI

#rm(list = ls())
library(shiny)
app <- shinyApp(
  ui = bootstrapPage(
    uiOutput("myList"),
    actionButton("acb1", "Change Value"),
    actionButton("acb2", "Change Value to Range")
  ),
  server = function(input, output, session) {

    slidertype <- reactiveValues()
    slidertype$type <- "default"

    observeEvent(input$acb1,{slidertype$type <- "normal"})
    observeEvent(input$acb2, {slidertype$type <- "range"})

    output$myList <- renderUI({

      if(slidertype$type == "normal"){
        sliderInput("sld1", min = 0, max = 10, label = "y1", value = 2)
      }
      else if(slidertype$type == "range"){
        sliderInput("sld1", min = 0, max = 10, label = "y1", value = c(2,7))
      }
      else{
        sliderInput("sld1", min = 0, max = 10, label = "y1", value = 5)
      }
    })    
})
runApp(app)
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