Image Literals, Arrays and randomizing in Swift. Why does this method work but the other doesn'-CodePudding

Creating a dice roll app following Angela Yu's App Brewery bootcamp on Udemy. She uses image literals but those seem to have been deprecated on newer versions of Xcode.

I get the error: Cannot assign value of type 'UIImage??' to type 'UIImage?' Whenever I try to use diceArray.randomElement()

However, diceArray[Int.random(in:0...5] seems to work fine. My suspicion is maybe to use .randomElement() I need to use imageView but new to Swift so not sure if this is correct or what the difference even is. Any explanation would be appreciated. Thanks.

      @IBAction func rollButtonPressed(_ sender: UIButton) {
            
            
           var diceArray = [UIImage(named: "DiceOne"),UIImage(named: "DiceTwo"),UIImage(named: "DiceThree"),UIImage(named:"DiceFour"),UIImage(named:"DiceFive"),UIImage(named:"DiceSix")]
           
            diceImageView1.image = diceArray.randomElement()
            diceImageView2.image = diceArray[Int.random(in: 0...5)]
          
            
        }

CodePudding user response：

UIImage(named: initializer returns UIImage? and randomElement returns an Optional so it's ?? , you can force it

diceImageView1.image = diceArray.randomElement()!

CodePudding user response：

As Sh_Khan pointed out, you have an array of Optionals since UIImage.named(_:) returns an Optional.

I would suggest adding a call to compactMap at the end of your code that declares your array of images:

var diceArray = [UIImage(named: "DiceOne")…].compactMap { $0 }

That will make diceArray an array of UIImages instead of Optional(UIImage) (and strip out any failed attempts to load images.)