Update DT table dropdowns with reactive data in shiny

General
,
2

I think the problem is that you are re-using the selectInput id's while they have not been cleared from the page yet. One way you can overcome this is by generating new id's each time the number is changed. There could be better/more efficient solutions but this seems to work.

library(shiny)
library(DT)

ui <- fluidPage(
  title = 'Selectinput column in a table',
  h3("Source:", tags$a("Yihui Xie", href = "https://yihui.shinyapps.io/DT-radio/")),
  numericInput('num', "enter a number", value = 5, min = 1, max = 10, step = 1),
  DT::dataTableOutput('foo'),
  verbatimTextOutput('sel')
)

server <- function(input, output, session) {
  
  counter <- reactiveVal(0)
  get_sel_id <- reactive({
    input$num
    isolate(counter(counter() + 1))
    paste0("sel", counter())
  })
  
  data <- reactive({
    df <- head(iris, input$num)
    
    for (i in 1:nrow(df)) {
      df$species_selector[i] <- as.character(selectInput(paste0(get_sel_id(), i),
                                                           "",
                                                           choices = unique(iris$Species),
                                                           width = "100px"))
    }
    df
  })
  
  output$foo = DT::renderDataTable(
    data(), escape = FALSE, selection = 'none', server = FALSE,
    options = list(dom = 't', paging = FALSE, ordering = FALSE),
    callback = JS("table.rows().every(function(i, tab, row) {
        var $this = $(this.node());
        $this.attr('id', this.data()[0]);
        $this.addClass('shiny-input-container');
      });
      Shiny.unbindAll(table.table().node());
      Shiny.bindAll(table.table().node());")
  )
  output$sel = renderPrint({
    str(sapply(1:nrow(data()), function(i) input[[paste0(get_sel_id(), i)]]))
  })
}

shinyApp(ui, server)