Shiny dynamically select element in list and renderTable

Question

I have a list l of data.frames, and I want to dynamically select elements with selectInput.

Once the user selects an element, I'd like to be able work with it under the hood, for example use it in renderTable and output a table of that data.frame.

Moreover I'd like to be able to select that element in the list, and apply lm for example.

The problem I'm facing is here: l[[ElemInput()]] how do I convert this classic R code with a reactive element?

Here the complete shinydashboard:

library(shiny)
library(shinydashboard)


ui <- dashboardPage(
  dashboardHeader(
    title = "My Dashboard"
  ),
  dashboardSidebar(
    sidebarMenu(
      menuItem("aaa", tabName = "aaa", icon = icon("dashboard"))
    )
  ),
  dashboardBody(
    tabItems(
      # First tab content
      tabItem(tabName = "aaa",
              h2("Dashboard aaa"),
              fluidRow(
                box(
                    selectInput("input_name", "Select input:", choices = names(l))
                ),
                box(
                  dataTableOutput('table')
                )
              )
      )
    )
  )
)

server <- function(input, output) { 
  # create a fake list 
  set.seed(123)
  l <- list(element1 = data.frame(aaa=1:5, bbb=sample(5)),
            element2 = data.frame(ccc=6:10, ddd=sample(5)))

  # reactive read element
  ElemInput <- reactive({
    input$input_name
  })

  # render table
    output$table <- renderTable({
      l[[ElemInput()]] #  this part doesn't work
    })

}

shinyApp(ui, server)

Possibly correlated questions but I couldn't figure out a solution for my case:

dynamically list 'choices' for selectInput from a user selected column

Store selectInput in a string/character object

score 1 · Accepted Answer · answered Dec 05 '18 at 10:16

You should use renderTable with tableOutput in your ui. So change dataTableOutput('table') to tableOutput('table').

You can use dataTableOutput if you use renderDataTable though.

Also my I prefer to use an observer instead of a reactive function. It's a bit easier to read.

server <- function(input, output) { 
  observeEvent(input$input_name,{
    # observe element change and render table
    output$table <- renderTable({
      data.frame(l[[input$input_name]])
    })
  })
}

Shiny dynamically select element in list and renderTable

1 Answers1