how to show contents of uploaded csv in shiny - shiny

Question

My ui.R
library(shiny)
library(stats)
library(caret)
shinyUI(fluidPage(
titlePanel("Predicting Resources for Vessel"),
title = "Resource Prediction",
sidebarLayout(
sidebarPanel(
fileInput("file1", "Choose a Import BAPLE(.CSV) file to upload:",
accept = c("text/csv", "text/comma-separated-values, text/plain", ".csv")),
fileInput("file2", "Choose a Export BAPLE(.csv) file to upload:",
accept = c("text/csv", "text/comma-separated-values, text/plain", ".csv")),
fileInput("file3", "Choose a Import/Export containers yard location(.CSV) file to upload:",
accept = c("text/csv", "text/comma-separated-values, text/plain", ".csv")),
tags$hr(),
h4("Manual Input:"),
numericInput("Restow_40","Total Restows for 40ft Container:", 0, min = 0, max = 999999, step = 1),
textInput("Berth","Vessel Berth Location (CB3/CB4)"),
actionButton("submit", "Submit")
),
mainPanel(
tabsetPanel(
tabPanel("Raw Data", dataTableOutput("data")),
tabPanel("Output", verbatimTextOutput("pred_output"))
)
)
)
))
This is my server.r file
library(shiny)
library(stats)
#library(caret)
library(mlr)
library(data.table)
shinyServer(function(input, output) {
######################### Reading the required files ###################################
import_baple <- reactive({
inFile <- input$file1
if (is.null(inFile)) return(NULL)
read.csv(inFile$datapath)
})
export_baple <- reactive({
inFile <- input$file2
if (is.null(inFile)) return(NULL)
read.csv(inFile$datapath)
})
import_export_yard <- reactive({
inFile <- input$file3
if (is.null(inFile)) return(NULL)
read.csv(inFile$datapath)
})
output$data <- renderDataTable({
import_baple()
})
output$data <- renderDataTable({
export_baple()
})
output$data <- renderDataTable({
import_export_yard()
})
})
I want all the three files when uploaded to be displayed in Raw Data tab. When I upload first two files no content is displayed in the Raw Tab, but when I upload the third file content is displayed in the tab. I am not getting where I am doing it wrong.

Answer 1

Each input/output element needs a unique identifier, otherwise Shiny doesn't know which of the elements with the given identifier to use. So where you have:
tabPanel("Raw Data", dataTableOutput("data"))
In your UI and:
output$data <- renderDataTable({
import_baple()
})
output$data <- renderDataTable({
export_baple()
})
output$data <- renderDataTable({
import_export_yard()
})
In your server, what you actually need is more like:
# UI
tabPanel("Raw Data",
dataTableOutput("import_baple_data"),
dataTableOutput("explort_baple_data"),
dataTableOutput("import_export_data")
)
# Server
output$import_baple_data <- renderDataTable({
import_baple()
})
output$export_baple_data <- renderDataTable({
export_baple()
})
output$import_export_data <- renderDataTable({
import_export_yard()
})