title: Issues while adding and deleting row in R shiny datatable
body: <p>I am trying to add an editable datatable in r shiny. I have two components to it. First being allowing the user to add a new row and delete a selected row. Secondly when the user changes any value in the cell it should update the corresponding cell. The issue I am facing first off is to unable to delete selected rows. I am able to add those but not delete. Below is the code which I am using. Also I am trying to reset to a default table but it wont reset to the default table. How can I fix this. Thank you.</p>
  
  <pre><code>### Libraries
  library(shiny)
  library(dplyr)
  library(DT)
  
  ### Data
  input_data &lt;- data.frame(aa = c("Brand1", "Brand2","Brand3"),
                           bb = c(2000, 3000, 4000),
                           cc = c (.5, .5, .5),
                           dd = c(2000, 3000, 4000),
                           ee = c (.5, .5, .5),
                           ff = c (.5, .5, .5),
                           gg = c (.5, .5, .5),
                           stringsAsFactors = FALSE)
  
  ### Shiny App
  shinyApp(
    ui = basicPage(
      mainPanel(
  
        actionButton("reset", "Reset"),
        actionButton("add_btn", "Add"),
        actionButton("delete_btn", "Delete"),
        tags$hr(),
        DT::dataTableOutput("mod_table")    )
    ),
    server = function(input, output) {
  
      #demodata&lt;-input_data
  
      this_table &lt;- reactiveVal(input_data)
  
      observeEvent(input$add_btn, {
        t = rbind(data.frame(aa = "default",
                             bb = 1000000,cc = 2.0,dd = 20000, ee = 40,ff = 00 , gg = 00), this_table())
        this_table(t)
      })
  
      observeEvent(input$delete_btn, {
        t = this_table()
        print(nrow(t))
        if (!is.null(input$shiny_table_rows_selected)) {
          t &lt;- t[-as.numeric(input$shiny_table_rows_selected),]
        }
        this_table(t)
      })
  observeEvent(input$reset, {
         this_table &lt;- input_data # your default data
       })
  
      output$mod_table &lt;- DT::renderDataTable({
        datatable(this_table(), selection = 'single',editable = TRUE, options = list(dom = 't'))
  
      })
      }
  )
  
  </code></pre>