title: How to match values in two TableViews
body: <p>There is a tableview with folder names and after clicking on each row, it segues to another TableView to show sections and rows for each folder. But I got problem how to show values corresponding to every folder. The error message is: fatal error: unexpectedly found nil while unwrapping an Optional value.  Please see my codes below. I guess the problem is prepareForSegue codes didn't work well. </p>
  
  <p>Note: Somewhere I need to delete half ")" as it doesn't work for "()" and I can't edit.  Please help to edit. </p>
  
  <p>In first tableview:</p>
  
  <pre><code>var folderNames = [String]()
  
  override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
  
          if segue.identifier == segueToDetailsTable {
  
              let detailsVC = segue.destinationViewController as! DetailsViewController
  
              detailsVC.detailsTableView.indexPathForCell(UITableViewCell(style: UITableViewCellStyle.Value1, reuseIdentifier: "DetailsCell")) == savingTableView.indexPathForSelectedRow
  
  
          }
  
      }
  </code></pre>
  
  <p>In second TableView to show details:</p>
  
  <pre><code>var sectionTitles = ["WebSite", "Date Saved", "Document Used","Add Notes"]
  
  var detailsInSection = [[String](), [NSDate](),[AnyObject](),[String]()]
  
  func numberOfSectionsInTableView(tableView: UITableView) -&gt; Int {
  
          return detailsInSection.count
      }
  
      func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -&gt; String? {
  
          return sectionTitles[section]
      }
  
  
      func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int {
  
          return detailsInSection[section].count
      }
  
      func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -&gt; UITableViewCell {
  
          let cell = tableView.dequeueReusableCellWithIdentifier("DetailsCell")
  
          cell?.textLabel!.text = detailsInSection[indexPath.section][indexPath.row].description
  
          return cell!
      }
  </code></pre>