R Shiny Make slider value dynamic

Question

I've got a dropdown selector and a slider scale. I want to render a plot with the drop down selector being the source of data. - I've got this part working

I simply want the slider's max value to change based on which dataset is selected.

Any suggestions?

server.R

library(shiny)
shinyServer(function(input, output) {

source("profile_plot.R")
load("test.Rdata")

output$distPlot <- renderPlot({
  if(input$selection == "raw") {
    plot_data <- as.matrix(obatch[1:input$probes,1:36])
  } else if(input$selection == "normalised") {
  plot_data <- as.matrix(eset.spike[1:input$probes,1:36])
  } 

  plot_profile(plot_data, treatments = treatment, sep = TRUE)
  })
})

ui.R library(shiny)

shinyUI(fluidPage(
  titlePanel("Profile Plot"),

  sidebarLayout(
    sidebarPanel(width=3,
    selectInput("selection", "Choose a dataset:", 
                 choices=c('raw', 'normalised')),
    hr(),
    sliderInput("probes",
              "Number of probes:",
              min = 2,
              max = 3540,
              value = 10)
    ),
    mainPanel(
      plotOutput("distPlot")
    )
  )
))

Answer 1

As @Edik noted the best way to do this would be to use an update.. type function. It looks like updateSliderInput doesnt allow control of the range so you can try using renderUI on the server side:

library(shiny)
runApp(list(
  ui = bootstrapPage(
    numericInput('n', 'Maximum of slider', 100),
    uiOutput("slider"),
    textOutput("test")
  ),
  server = function(input, output) {
    output$slider <- renderUI({
      sliderInput("myslider", "Slider text", 1,
                  max(input$n, isolate(input$myslider)), 21)
    })

    output$test <- renderText({input$myslider})
  }
))