Shiny app for selecting a pair of players?

I am developing a shiny app for selecting a pair of players from the below dataset

structure(list(player = c("Samson", "Tausif", "charles", "vinod", 
"bhsoley", "sugandhey", "mohit", "ocd", "shankar", "sneha")), class = "data.frame", row.names = c(NA, 
-10L))

I am new to r and shiny by reading from multiple sources I am able to develop an app for random selection. the code is as shown below:

ui<-fluidPage(
  fileInput('datafile', 'Choose CSV file',
            accept=c('csv', 'comma-separated-values','.csv')),
  tableOutput('table'),
  tableOutput("table1")
)

server<- function(input, output,session) {
  dataframe<-reactive({
    if (is.null(input$datafile))
      return(NULL)                
    data<-read.csv(input$datafile$datapath)
    data
  })
  
  dataframe1<-reactive({
    if (is.null(input$datafile))
      return(NULL)                
    data1<-read.csv(input$datafile$datapath)
    y<-split(sample(data1),rep(1:5,each=2)) 
    df<-data.frame(matrix(unlist(y), nrow=length(y), byrow=T))
    df
  })
  output$table <- renderTable({
    dataframe()
  })
  output$table1 <- renderTable({
    dataframe1()
  })
}
shinyApp(ui, server)

but each time i run this, it generate the same result however the results are different pair of player in R terminal.

This is screenshot of my app

I am looking for a solution where each time I upload a CSV file it generate different player names.