Update Shiny's 'selectInput' dropdown with new values after uploading new data using fileInput

Question

I have a Shiny app that includes a number of dropdown selection boxes, the values of which are filled from reading an RDS file. The app also includes a fileInput function to

Answer 1

I added reactive object myData that you have to use for table contents, but more importantly to update choices in selectInput (check observe and updateSelectInput part).

library(shiny)

ui <- shinyUI(
    fluidPage(
        fileInput("file1", "Choose file to upload", accept = ".rds"),
        selectInput("myNames","Names", ""),
        tableOutput("contents")
    )
)

server <- function(input, output, session) {

    myData <- reactive({
        inFile <- input$file1
        if (is.null(inFile)) {
            d <- myDataFrame
        } else {
            d <- readRDS(inFile$datapath)
        }
        d
    })

    output$contents <- renderTable({
        myData()
    })

    observe({
         updateSelectInput(session, "myNames",
                           label = "myNames",
                           choices = myData()$names,
                           selected = myData()$names[1])
    })

}

shinyApp(ui, server)