title: Use datatable single cell selection to subset a dataframe in R shiny
body: <p>I have the shiny app below in which I want to be able to click on a certain column-single-and create a 2nd datatable with only this cell. The issue is that I cannot achieve this as I do it with row selection which gives back the row index which I use to subset. In this case I use a 1st row -3rd column example.</p>
  
  <pre><code>library(shiny)
  
  fluidPage(
  
    title = 'Select Table Rows',
  
  
    h1('A Server-side Table'),
  
    fluidRow(
      column(9, DT::dataTableOutput('x3')),
      column(3, DT::dataTableOutput('x4'))
    )
  
  )
  #server.r
     library(shiny)
  library(DT)
  
  shinyServer(function(input, output, session) {
  
    # server-side processing
    mtcars2 = mtcars[, 1:8]
    output$x3 = DT::renderDataTable(mtcars2, server = TRUE,selection=list(target='cell'))
  
    # print the selected indices
    output$x4 = DT::renderDataTable({
      if(as.character(input$x3_cells_selected)=="1, 3"){
        mtcars[1,3]
      }
  
    })
  
  })
  </code></pre>