Disallow words less than 3 characters

Question

In the Swift code below, the user chooses a word and types it into a text box, now how to disallow the words entered if less than 3 characters in length?

func isReal (word: String) -> Bool {
    //return true
    let checker = UITextChecker()
    let range = NSMakeRange(0, word.utf16.count)
    let misspelledRange = checker.rangeOfMisspelledWord(in: word, range: range, startingAt: 0, wrap: false, language: "en")
    return misspelledRange.location == NSNotFound
}

Answer 1

You can just add an if to check if the word has more than 3 characters:

func isReal (word: String) -> Bool {
    if word.characters.count >= 3 {
        //return true
        let checker = UITextChecker()
        let range = NSMakeRange(0, word.utf16.count)
        let misspelledRange = checker.rangeOfMisspelledWord(in: word, range: range, startingAt: 0, wrap: false, language: "en")
        return misspelledRange.location == NSNotFound
    } else {
        return false
    }
}

This way, if word is shorter than 3 characters, it will return false , otherwise, it will test against the UITextChecker() and then return true or false respectively

EDIT: Alternative using guard :

func isReal (word: String) -> Bool {
    guard word.characters.count >= 3 else {
        return false
    }

    //return true
    let checker = UITextChecker()
    let range = NSMakeRange(0, word.utf16.count)
    let misspelledRange = checker.rangeOfMisspelledWord(in: word, range: range, startingAt: 0, wrap: false, language: "en")
    return misspelledRange.location == NSNotFound
}

If the guard statement is not met (being word.characters.count < 3), the function will automatically return false

Answer 2

You can implement the didEndEditing UItextfieldDelegate method and then check 1) that its a single word and 2) that its longer than 2 characters. At that point you then need to show an error or a red caption label or something.

func textFieldDidEndEditing(_ textField: UITextField, reason: UITextFieldDidEndEditingReason) {
    guard let string = textField.text else {
        return
    }
    let characterSet = CharacterSet(charactersIn: string)
    if characterSet.intersection(CharacterSet.whitespacesAndNewlines).isEmpty != true {
        // we have white space!
    }
    if string.characters.count < 3 {
        // too short
    }
}

Answer 3

You don't need to implement new functions to check an input coming from a UITextField . UITextField has its own functions for that. You should make your ViewController class conform to the UITextFieldDelegate protocol, set it as the delegate for your UITextField , then implement the required delegate method, textFieldDidEndEditing and check the length of the input there.

extension YourViewController: UITextFieldDelegate {
    func textFieldDidEndEditing(_ textField: UITextField) {
        guard let input = textField.text else {return}
        if input.characters.count < 3 {
            //handle error
        }
    }
}

In viewDidLoad of YourViewController :

yourTextField.delegate = self