How to create Shiny R dynamic renderTable, with a number of tables determined by the uploaded CSV files?

Question

I am building web app that after uploading csv files transforms the data and then should be able to output few tables. The number of the tables depends strictly on the infor

Answer 1

A solution is to put everything inside an observe.

library(shiny)

ui <- fluidPage(
  fluidRow(column(3,
                  wellPanel(
                    fileInput(
                      inputId = "files",
                      label = "Choose cvs files",
                      accept = c('text/csv',
                                 'text/comma-separated-values,text/plain',
                                 '.csv'),
                      multiple = TRUE
                    )
                  )),
           column(5, offset = 1, uiOutput("tables"))))

server <- function(input, output) {
  observe({
    if (!is.null(input$files)) {
      max_table = length(input$files[, 1])

      lst <- list()
      for (i in 1:length(input$files[, 1])) {
        lst[[i]] <-
          read.csv(
            input$files[[i, 'datapath']],
            sep = ",",
            header = TRUE,
            skip = 4,
            dec = "."
          )
      }

      output$tables <- renderUI({
        plot_output_list <- lapply(1:max_table, function(i) {
          tablename <- paste("tablename", i, sep = "")
          tableOutput(tablename)
        })
        do.call(tagList, plot_output_list)
      })

      for (i in 1:max_table) {
        local({
          my_i <- i
          tablename <- paste("tablename", my_i, sep = "")
          output[[tablename]] <- renderTable({
            lst[[my_i]]
          })
        })
      }
    }
  })

}

shinyApp(ui = ui, server = server)