Appending Two String Arrays in Tuple - swift

Question

I am trying to append two Sting Arrays in tuple but it gives me error?
This is my class:
import UIKit
var tuple : [(String, String)] = []
class ViewController: UIViewController , UICollectionViewDelegate{
let reuseIdentifier = "cell"
var url : [String] = []
var image : [String] = []
override func viewDidLoad(){
}
override func viewWillAppear(animated: Bool) {
for i in tuple{
url.append(i.0)
image.append(i.1)
print("URL values.............. \(url)")
print("Image values.............. \(image)")
}
NSUserDefaults.standardUserDefaults().setObject(url, forKey: "u")
NSUserDefaults.standardUserDefaults().setObject(image, forKey: "i")
NSUserDefaults.standardUserDefaults().synchronize()
var u = NSUserDefaults.standardUserDefaults().objectForKey("u")
var i = NSUserDefaults.standardUserDefaults().objectForKey("i")
tuple.removeAll()
tuple.append(u,i)
}
When I change the types to this:
var u : String = NSUserDefaults.standardUserDefaults().objectForKey("u") as! String
var i : String = NSUserDefaults.standardUserDefaults().objectForKey("i") as! String
Now it gives me that error:
How can I append a tuple to an array?

Answer 1

[Code removed]
Also, as a user told you in comment, naming an array tuple is bad habit. The name tuples would fit already much better
EDIT: As #originaluser2 said, you can also use tuple.append((u,i))
EDIT2: I think this is definitely what you're looking for (I also adjusted names to avoid confusion, you should too)
import UIKit
class ViewController: UIViewController , UICollectionViewDelegate{
let reuseIdentifier = "cell"
var tuples: [(String, String)] = []
var urls: [String] = []
var images: [String] = []
override func viewDidLoad(){
}
override func viewWillAppear(animated: Bool) {
for i in tuples {
urls.append(i.0)
images.append(i.1)
print("URL values.............. \(urls)")
print("Image values.............. \(images)")
}
NSUserDefaults.standardUserDefaults().setObject(urls, forKey: "u")
NSUserDefaults.standardUserDefaults().setObject(images, forKey: "i")
NSUserDefaults.standardUserDefaults().synchronize()
// Cast objects as NSArray, since it's a subclass of NSObject
// Only NSObject derivate classes can be used for these purposes
let u = NSUserDefaults.standardUserDefaults().objectForKey("u") as! NSArray
let i = NSUserDefaults.standardUserDefaults().objectForKey("i") as! NSArray
tuples.removeAll()
// For every element of the first NSArray
for index in 0 ..< u.count {
// Append in the tuples array the strings at position index
// of both array
// NSString and String class are bridged, so you can use them both
// in order to accomplish your needs. An NSArray btw can store NSString, but not String objects
tuples.append((u.objectAtIndex(index) as! String,i.objectAtIndex(index) as! String))
}
}
}