快速检查数组元素

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? PS 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

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)
        }
    }
}

Answer 2

Try this:

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

Answer 3

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)
 }