title: Searching Columns in R shiny Datatable that has Multiple Entries
body: <p>I have a datatable in R Shiny, and one of the columns, Keywords, contains multiple entries for some rows, separated by a comma. I would like these multiple entries to be individually searchable. The default search feature for datatable treats these entries as one, long, single item.</p>
  
  <p>For example, row 2's value for the column Keywords is "Keyword1, Keyword2". I would like the user to be able to search for either "Keyword1" OR "Keyword2" and find row 2. Currently, the default search bar in datatable treats this entry as one item: "Keyword1, Keyword2" and only allows people to search for "Keyword1, Keyword2" as one, joint item, not two separate values.</p>
  
  <p>Here is a small, reproducible example of the problem</p>
  
  <pre><code>library(shiny)
  library(DT)
  
  ## Create an example dataset with 3 rows and 1 column
  dat &lt;- matrix(c("Keyword1", "Keyword1, Keyword2", "Keyword2"), nrow = 3, ncol = 1)
  colnames(dat) &lt;- "Keywords"
  dat &lt;- data.frame(dat)
  
  ui &lt;- shinyUI(
    DT::dataTableOutput('ex1')
  )
  
  server &lt;- shinyServer(function(input, output) {
    output$ex1 &lt;- DT::renderDataTable(
       DT::datatable(dat, filter = "top")
    )
  })
  
  shinyApp(ui = ui, server = server)
  </code></pre>