R shiny passing reactive to selectInput choices

by

You need to use renderUI on the server side for dynamic UIs. Here is a minimal example. Note that the second drop-down menu is reactive and adjusts to the dataset you choose in the first one. The code should be self-explanatory if you have dealt with shiny before.

runApp(list(
  ui = bootstrapPage(
    selectInput('dataset', 'Choose Dataset', c('mtcars', 'iris')),
    uiOutput('columns')
  ),
  server = function(input, output){
    output$columns = renderUI({
      mydata = get(input$dataset)
      selectInput('columns2', 'Columns', names(mydata))
    })
  }
))

EDIT. Another Solution using updateSelectInput

runApp(list(
  ui = bootstrapPage(
    selectInput('dataset', 'Choose Dataset', c('mtcars', 'iris')),
    selectInput('columns', 'Columns', "")
  ),
  server = function(input, output, session){
    outVar = reactive({
      mydata = get(input$dataset)
      names(mydata)
    })
    observe({
      updateSelectInput(session, "columns",
      choices = outVar()
    )})
  }
))

EDIT2: Modified Example using parse. In this app, the text formula entered is used to dynamically populate the dropdown menu below with the list of variables.

library(shiny)
runApp(list(
  ui = bootstrapPage(
    textInput("text", "Enter Formula", "a=b+c"),
    uiOutput('variables')
  ),
  server = function(input, output){
    outVar <- reactive({
      vars <- all.vars(parse(text = input$text))
      vars <- as.list(vars)
      return(vars)
    })

    output$variables = renderUI({
      selectInput('variables2', 'Variables', outVar())
    })
  }
))

More Related Contents:

  1. How to listen for more than one event expression within a Shiny observeEvent
  2. R Shiny: Handle Action Buttons in Data Table
  3. dynamically add plots to web page using shiny
  4. How to listen for more than one event expression within a Shiny eventReactive handler
  5. How to save plots that are made in a shiny app
  6. R Shiny: reactiveValues vs reactive
  7. drop-down checkbox input in shiny
  8. Shiny: what is the difference between observeEvent and eventReactive?
  9. how to create two independent drill down plot using Highcharter?
  10. How to change ‘Maximum upload size exceeded’ restriction in Shiny and save user file inputs?
  11. Subset based on variable column name
  12. Formatting reactive data.frames in Shiny
  13. Favicon in Shiny
  14. Shiny: Merge cells in DT::datatable
  15. RStudio Shiny ERROR: there is no package called “shinydashboard”
  16. R Shiny Dynamic Input
  17. What is “object of type ‘closure’ is not subsettable” error in Shiny?
  18. Shiny: passing input$var to aes() in ggplot2
  19. How to embed an image in a cell a table using DT, R and Shiny
  20. Show content for menuItem when menuSubItems exist in Shiny Dashboard
  21. shinydashboard some Font Awesome Icons Not Working
  22. Passing data within Shiny Modules from Module 1 to Module 2
  23. Edit datatable in Shiny with dropdown selection for factor variables
  24. Scale and size of plot in RStudio shiny
  25. Are there global variables in R Shiny?
  26. Data input via shinyTable in R shiny application
  27. ToolTip when you mouseover a ggplot on shiny
  28. Set global object in Shiny
  29. Shiny – observe() triggered by dynamicaly generated inputs
  30. date format in tooltip of ggplotly

Leave a Comment