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Project 9 | Day 40 | Challenge 2 | Is it good practice to mix performSelector and DispatchQueue?

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Hello everyone! I hope you're all safe and well.

I am using both performSelector and DispatchQueue to solve Challenge 2 in Project 9 and although it works, I'm not sure if this is the right approch. Any thougths?

Note: Whenever I call loadLevel (in viewDidLoad and levelUp), I use: performSelector(inBackground: #selector(loadLevel), with: nil)

@objc func loadLevel() {
        var clueString = ""
        var solutionsString = ""
        var letterBits = [String]()

        if let levelFileURL = Bundle.main.url(forResource: "level\(level)", withExtension: "txt") {
            if let levelContents = try? String(contentsOf: levelFileURL) {
                var lines = levelContents.components(separatedBy: "\n")

                for (index, line) in lines.enumerated() {
                    let parts = line.components(separatedBy: ": ")
                    let answer = parts[0]
                    let clue = parts[1]

                    clueString += "\(index + 1). \(clue)\n"

                    let solutionWord = answer.replacingOccurrences(of: "|", with: "")
                    solutionsString += "\(solutionWord.count) letters\n"

                    let bits = answer.components(separatedBy: "|")
                    letterBits += bits

        DispatchQueue.main.async { [weak self] in
            self?.cluesLabel.text = clueString.trimmingCharacters(in: .whitespacesAndNewlines)
            self?.answersLabel.text = solutionsString.trimmingCharacters(in: .whitespacesAndNewlines)
            debugPrint(self?.answersLabel.text ?? "answersLabel is empty")
            debugPrint("Solutions array = \(self!.solutions)")


            if self?.letterButtons.count == letterBits.count {
                for i in 0..<self!.letterButtons.count {
                    self?.letterButtons[i].setTitle(letterBits[i], for: .normal)


Hi. I didn't try mixing the 2 approaches, but perhaps it could be best to stick to one style for consistency sake. Have fun!


My first inclination was to do it this way as well, seemed to work just fine lol.


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