r shiny uploaded file calculations

[suparna_hazra]

In shiny application after uploading two excel files I am unable to do calculations with these uploaded files how to do that can you please help?
library(shiny)
library(readxl)

    shinyUI(fluidPage({
        titlePanel("Use readxl")
        sidebarLayout(
            sidebarPanel(
                fileInput('file1', 'Choose xlsx file1',
                          accept = c(".xlsx")),
                fileInput('file2', 'Choose xlsx file2',
                                    accept = c(".xlsx")),
                selectInput("Analytical operation", "Operation:",
                            c("Add" = "add",
                              "Multiply" = "mult",
                              "Join" = "join"))
                
                
            ),
            
            mainPanel(
                #tableOutput('contents'),
                #tableOutput('contents1'))
            tabsetPanel(
              tabPanel(strong("Training dataset"), tableOutput("contents"),
                       strong("Test dataset"),tableOutput("contents1") ),
              tabPanel("Result")
            )
        )
        )
    })
    
)
    shinyServer(function(input, output){
output$contents <- renderTable({
    inFile <- input$file1
    
    if(is.null(inFile))
        return(NULL)
    file.rename(inFile$datapath,
                paste(inFile$datapath, ".xlsx", sep=""))
    read_excel(paste(inFile$datapath, ".xlsx", sep=""), 1)
})
output$contents1 <- renderTable({
    inFile1<- input$file2
    
    if(is.null(inFile1))
        return(NULL)
    file.rename(inFile1$datapath,
                paste(inFile1$datapath, ".xlsx", sep=""))
    read_excel(paste(inFile1$datapath, ".xlsx", sep=""), 1)
})
data <- reactive({
    req(input$infile1)
    read_xlsx(input$infile1$datapath)
})

}
)

[andresrcs]

Could you be more specific? What calculations you want to perform?