Display the variables from the uploaded file and change their datatype.

[Deepthi Rajkumar]

Hello Group, 

I am trying to develop a application, where the user can upload the file. The variables from the uploaded file should be displayed in the form of group checkbox and convert their datatype into numeric or date format according to user selection.

I have designed the dashboard in such a way that I have two sub menu items. Sub menu item 1, has loading of file and sub menu item 2 has preparation section.

With my below code, I have two problems. 

1. The selection of variables are displayed in the Load menu instead of prep

2. Also, the render UI for variables, are displaying some irrelevant information and not the information I need.

Below is my code , that I have tried so far,

library(shinydashboard)

ui<-dashboardPage(
  dashboardHeader(title = "Model"),
  dashboardSidebar(
    sidebarMenu(id="tabs",
                menuItem("Data", tabName = "data", icon = icon("table"),startExpanded = TRUE,
                         menuSubItem("Load", tabName = "data1"),
                         menuSubItem("Prep", tabName = "prep")
                ),
                menuItem("Visualisation",icon=icon("bar-chart-o"), tabName = "vis"),
                menuItem("Result", icon=icon("cog"), tabName = "result")
    )
  ),
  dashboardBody(
    tags$style(type="text/css",
               ".shiny-output-error { visibility: hidden; }",
               ".shiny-output-error:before { visibility: hidden; }"
    ),
    tabItems(
      tabItem(tabName = "data1",
              fluidPage(
                fluidRow(
                  fileInput("file1","Choose CSV File",
                            accept = c("text/csv",
                                       "text/comma-seperated-values, text/plain",
                                       ".csv")
                  ),
                  tags$hr(),
                  checkboxInput("header", "Header", TRUE),
                  radioButtons("sep","Separator",
                               choices=c(Comma=",",
                                         semicolon=";",
                                         Tab="\t"),
                               selected = ";")
                ),
                mainPanel(
                  uiOutput("tb")
                )
              )
      )
    ),
    tabItem(tabName = "prep",
            fluidPage(
              fluidRow(
                 mainPanel(
                   uiOutput("Pre")
                 )
              )
            ))
  )
) 


server <- shinyServer(function(input,output){
  data <- reactiveVal()

  observeEvent(input$file1, ignoreNULL = T, ignoreInit = T,{
    file1 <- input$file1
    if(is.null(file1)){return()}
    read.csv(file = file1$datapath, sep=input$sep)
  })

  output$filedf <- renderTable({
    if(is.null(data())){return()}
    input$file1
  })
  output$sum <- renderTable({
    if(is.null(data())){return()}
    summary(data())
  })
  output$table <- renderTable({
    if(is.null(data())){return()}
    data()
  })
  output$tb <- renderUI({
    if(is.null(data())){return()}
    tabsetPanel(tabPanel("About file", tableOutput("filedf")),tabPanel("Data", tableOutput("table")),tabPanel("Summary", tableOutput("sum")))

  })

#----- Data Preparation------
  observeEvent({input$data_option
               input$data},
               {
                 if(input$data_option=="var_attr"&
                    !is.null(input$data)
                 ){
                   var.names <- names(input$data)
                   var.class <- NULL
                 }
})

})

shinyApp(ui,server)

Can anyone guide me , how i could avoid the error and achieve my target. I am unsure on how I could later convert the datatype for them.