Get selected columns in DT table

Question

I am developing a shiny app where user can select multiple columns in a big dataset to create a subset of this dataset. I use the package DT to render the table nicely in the shiny app.

I previously used version 0.2 of DT package where the following code was working :

library("DT")
library("shiny")

ui <- fluidPage(
  DT::dataTableOutput('table1'),
  DT::dataTableOutput("table2")
)

server <- function(input, output) {
  output$table1 <- DT::renderDataTable({
    datatable(mtcars, extensions = 'Select', selection = 'none', options = list(ordering = FALSE, searching = FALSE, pageLength = 25, select = list(style = 'os', items = 'column')),
              callback = JS(
                "table.on( 'click.dt', 'tbody td', function (e) {",
                "var type = table.select.items();",
                "var idx = table[type + 's']({selected: true}).indexes().toArray();",
                "var DT_id = table.table().container().parentNode.id;",
                "Shiny.onInputChange(DT_id + '_columns_selected', idx);",
                "})"
              ))
  })

  output$table2 <- DT::renderDataTable({
    subset_table <- mtcars[,input$table1_columns_selected]
    datatable(subset_table)
  })
}

shinyApp(ui = ui, server = server)

Unfortunately, this code is not working anymore (I am now under version 0.4). The input$table1_columns_selected does not render the indices of the selected columns. According to this https://rstudio.github.io/DT/shiny.html there is now a functionnality to select multiples rows, but I can't figure out how to do the same with columns.

Any idea ? Thank you very much for your help !

Answer 1

I am not sure why you need to use the callback argument to do this. Here's a simplified approach -

library("DT")
library("shiny")

ui <- fluidPage(
  DT::dataTableOutput('table1'),
  DT::dataTableOutput("table2")
)

server <- function(input, output) {
  output$table1 <- DT::renderDataTable({
    datatable(mtcars, extensions = 'Select', selection = list(target = "column"), options = list(ordering = FALSE, searching = FALSE, pageLength = 25))
  })

  output$table2 <- DT::renderDataTable({
    subset_table <- mtcars[, input$table1_columns_selected, drop = F]
    datatable(subset_table)
  })
}

shinyApp(ui = ui, server = server)

Note the change in the datatable arguments in output$table1 . Hope this is what you were looking for.

Answer 2

I have tested your code and its working fine for me (see picture below) and i am also using DT package version 0.4.

So my guess is that, its not DT package problem but something else in your global configuration that is causing the issue.