RStudio Shiny list from checking rows in dataTables

For the first problem you need the dev version of shiny and htmltools >= 0.2.6 installed:

# devtools::install_github("rstudio/htmltools")
# devtools::install_github("rstudio/shiny")
library(shiny)
runApp(list(ui = fluidPage(
  title = 'Row selection in DataTables',
  sidebarLayout(
    sidebarPanel(textOutput('rows_out')),
    mainPanel(dataTableOutput('tbl')),
    position = 'right'
  )
)
, server = function(input, output) {
  output$tbl <- renderDataTable(
    mtcars,
    options = list(pageLength = 10),
    callback = "function(table) {
    table.on('click.dt', 'tr', function() {
    $(this).toggleClass('selected');
    Shiny.onInputChange('rows',
    table.rows('.selected').indexes().toArray());
    });
}"
  )
  output$rows_out <- renderText({
    paste(c('You selected these rows on the page:', input$rows),
          collapse = ' ')
  })
}
)
)

for your second example:

library(shiny)
mymtcars = mtcars
mymtcars$id = 1:nrow(mtcars)
runApp(
  list(ui = pageWithSidebar(
    headerPanel('Examples of DataTables'),
    sidebarPanel(
      checkboxGroupInput('show_vars', 'Columns to show:', names(mymtcars),
                         selected = names(mymtcars))
      ,textInput("collection_txt",label="Foo")
    ),
    mainPanel(
      dataTableOutput("mytable")
    )
  )
  , server = function(input, output, session) {
    rowSelect <- reactive({
      paste(sort(unique(input[["rows"]])),sep=',')
    })
    observe({
      updateTextInput(session, "collection_txt", value = rowSelect() ,label = "Foo:" )
    })
    output$mytable = renderDataTable({
      addCheckboxButtons <- paste0('<input type="checkbox" name="row', mymtcars$id, '" value="', mymtcars$id, '">',"")
      #Display table with checkbox buttons
      cbind(Pick=addCheckboxButtons, mymtcars[, input$show_vars, drop=FALSE])
    }, options = list(orderClasses = TRUE, lengthMenu = c(5, 25, 50), pageLength = 25)
    , callback = "function(table) {
    table.on('change.dt', 'tr td input:checkbox', function() {
      setTimeout(function () {
         Shiny.onInputChange('rows', $(this).add('tr td input:checkbox:checked').parent().siblings(':last-child').map(function() {
                 return $(this).text();
              }).get())
         }, 10); 
    });
}")
  }
  )
)

This answer has been rendered broken in shiny 0.11.1, but can easily be fixed. Here is the update that did it (link):

Added an escape argument to renderDataTable() to escape the HTML entities in the data table for security reasons. This might break tables from previous versions of shiny that use raw HTML in the table content, and the old behavior can be brought back by escape = FALSE if you are aware of the security implications. (#627)

Thus, to make the previous solutions work, one must specify escape = FALSE as an option to renderDataTable().