Array element checking in swift

Question

Currently implementing a favourite function to my application which is based on quotes. I would like to perform a check for if the user has already saved an element to an array. If they have, I would change a favour button to unfavour button.
import UIKit

class DreamViewController: UIViewController {

    @IBOutlet var liketext: UIButton!
    @IBOutlet var QuoteImage: UIImageView!
    @IBOutlet weak var DreamLabel: UILabel!
    var counter = 1

    var factIndex = 0

    let dreamFact = Dream()

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        DreamLabel.text = dreamFact.dreamArray[factIndex]
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    @IBAction func LeftSwipe() {
        factIndex--
        var number = dreamFact.dreamArray.count - 1
        if (factIndex < 0){
            self.factIndex = number

        }
        DreamLabel.text = dreamFact.dreamArray[factIndex]
        if counter == 1 {

            counter = 36

        } else {

            self.counter--

        }

        QuoteImage.image = UIImage(named: "frame\(counter).jpg")

    }
@IBAction func RightSwipe() {
        factIndex++
        if factIndex >= dreamFact.dreamArray.count {
            self.factIndex = 0
        }
        DreamLabel.text = dreamFact.dreamArray[factIndex]
    if counter == 36 {

    counter = 1

    } else {

    self.counter++

    }
    QuoteImage.image = UIImage(named: "frame\(counter).jpg")
}
    struct Constants {
        static let defaults = NSUserDefaults.standardUserDefaults()
        static let fqKey = "FavoriteQuotes"
        static let like = "Like"
        static let unlike = "Unlike"
    }
    class DreamViewController {




        var favouriteQuotesArray = Constants.defaults.objectForKey(Constants.fqKey) as? [String] ?? [String]() {
            didSet {
                Constants.defaults.setObject(favouriteQuotesArray, forKey: Constants.fqKey)
            }



    }

         @IBOutlet weak var likeButton: UIButton! {

            didSet {
                let favourite = dreamArray[factIndex]
                if let foundIndex = find(favouriteQuotesArray, favourite) {
                    likeButton.setTitle(Constants.unlike, forState: .Normal)
                }
                else {
                    likeButton.setTitle(Constants.like, forState: .Normal)
                }
            }



        }

        @IBAction func likeButtonClicked(sender: UIButton) {
        }

        }
}

The dependency on upon the text which is unreliable because if the user reopens the app, the element would still be saved instead of starting out with the default unlike. If the element is found in the array. How would I perform a search inside my favouriteQuotesArray if the element exists like:

if elementfound statement {

button.settitle(unlike)
removearrayatindex statement.

} else {
button.settitle(like)
makeQuoteFavourite()
}

How would the array checking statement look like? P.S If you can please give tips on building the delete class? Update:

 var favouriteQuotesArray: [String] = NSUserDefaults.standardUserDefaults().objectForKey("thekey") as! [String]

    func makeQuoteFavourite() {
        if favouriteQuotesArray == nil {
            favouriteQuotesArray = []
        }
        let currentQuote = dreamFact.dreamArray[factIndex]
        favouriteQuotesArray.append(currentQuote)
        NSUserDefaults.standardUserDefaults().setObject(favouriteQuotesArray, forKey: "thekey")
    }
    @IBAction func likeButton() {

        if contains(favouriteQuotesArray, dreamFact.dreamArray[factIndex]) {
        liketext.setTitle("Unlike", forState: UIControlState.Normal)
        }

Answer 1

The better and quick way to find out an element in an array is:

if contains(yourFavArray, stringStatement){
  //Contains you can write your logic
}

Change your favouriteArray as below:

var favouriteQuotesArray: [String] = NSUserDefaults.standardUserDefaults().objectForKey("thekey") as! [String]

Edited:

 if let foundIndex = find(favouriteQuotesArray, dreamFact.dreamArray[factIndex]) {
     sender.setTitle(Constants.like, forState: .Normal)
     favouriteQuotesArray.removeAtIndex(foundIndex)
 }

Answer 2

Try this:

let currentQuote = dreamFact.dreamArray[factIndex]
if find(favouriteQuotesArray!, currentQuote) != nil {
    //Do something
}

Answer 3

Do it this way; some cleaner coding techniques to cut through the rubble included.

The declaration of favouriteQuotesArray is a gold star one liner. Got it all?

import UIKit

struct Constants {
    static let defaults = NSUserDefaults.standardUserDefaults()
    static let fqKey = "FavoriteQuotes"
    static let like = "Like"
    static let unlike = "Unlike"
}

class Page2ViewController: UIViewController {
    var dreamArray = [String]() // place holder so class compiles
    var factIndex = 0           // place holder so class compiles

    var favouriteQuotesArray = Constants.defaults.objectForKey(Constants.fqKey) as? [String] ?? [String]() {
        didSet {
            Constants.defaults.setObject(favouriteQuotesArray, forKey: Constants.fqKey)
        }
    }

    @IBOutlet weak var likeButton: UIButton! {
        didSet {
            let favourite = dreamArray[factIndex]
            if let foundIndex = find(favouriteQuotesArray, favourite) {
                likeButton.setTitle(Constants.unlike, forState: .Normal)
            }
            else {
                likeButton.setTitle(Constants.like, forState: .Normal)
            }
        }
    }

    @IBAction func likeButtonClicked(sender: UIButton) {
        let favourite = dreamArray[factIndex]
        if let foundIndex = find(favouriteQuotesArray, favourite) {
            sender.setTitle(Constants.like, forState: .Normal)
            favouriteQuotesArray.removeAtIndex(foundIndex)
        }
        else {
            sender.setTitle(Constants.unlike, forState: .Normal)
            favouriteQuotesArray.append(favourite)
        }
    }
}