Swift indexpath = optional(0) - ios

Question

i am trying to build my first iOS app with swift. I am stuck at a segue where i want to give the row indexpath to the next page, but the indexpath is "optional(0)" instead of "0". does anyone know why? in the code, there's a print sender. That one says "optional(0)" The variable "viewController.passedValue" is set to 0, the real code is behind it in comments
does anyone know why it gives "Optional(0)"?
Code:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let viewController = segue.destinationViewController as! NewsDetailViewController
print(String(sender))
viewController.passedValue = 0 // sender as! int
}
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
performSegueWithIdentifier("DetailSegue", sender: indexPath.row)
print("HIER")
}

Answer 1

You are calling
performSegueWithIdentifier("DetailSegue", sender: indexPath.row)
And then, iOS is calling your prepareForSegue, in which sender is defined as an AnyObject?, i.e. an optional AnyObject:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
...
}
Thus, when you print sender, it's an optional and thus informs you of such. If you don't want the optional, you could unwrap it (either forced unwrapping or, better, optional binding).
--
As an aside, though, it is a misuse of sender to be storing the indexPath.row there. As the documentation for performSegueWithIdentifier says, the sender is:
The object that you want to use to initiate the segue. This object is made available for informational purposes during the actual segue.
But indexPath.row is not the object that initiated the segue (the table view cell is). I therefore would advise against using the sender to hold the indexPath.row. A more common pattern would be
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let destination = segue.destinationViewController as? NewsDetailViewController, let row = tableView.indexPathForSelectedRow?.row {
destination.passedValue = row
}
}
This also has the virtue of giving you the alternative of not defining a didSelectRowAtIndexPath at all, and just represent your segue from the storyboard's cell prototype directly to the NewsDetailViewController scene. If you really want to segue programmatically, you can do that, but it's not necessary. But I would not advise using sender to represent the indexPath.row, but rather the UI control that triggered the segue.