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
}

Is the input coming from a `UITextField`? `UITextChecker` was designed to check spelling issues, not arbitrary input constraints, so you shouldn't use that. — Dávid Pásztor, Sep 12 '17 at 14:29
sorry i'm not getting you ... ! the input is by the user in the textField yes ... this is what i want to do here ---> Disallow answers that are shorter than three letters. The easiest way to accomplish this is to put a check into isReal() that returns false if the word length is under three letters, the question is ..... How ? — Amir Fendi, Sep 12 '17 at 14:35

Dante Puglisi · Accepted Answer · 2017-09-12T14:45:06.350

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

edited Sep 12 '17 at 14:45

answered Sep 12 '17 at 14:36

Dante Puglisi

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The `else` statement is not necessary but it's clearer this way – Dante Puglisi Sep 12 '17 at 14:37
actually i want to limit the answers to be minimum of 3 characters not less than that .... – Amir Fendi Sep 12 '17 at 14:39
2

@DantePuglisi, `guard` instead of `if/else` would be even clearer. – user28434'mstep Sep 12 '17 at 14:41
2

@user28434 totally, will add it as an alternative – Dante Puglisi Sep 12 '17 at 14:41
how to use guard ? – Amir Fendi Sep 12 '17 at 14:42
1

@AmirFendi I added it to the answer – Dante Puglisi Sep 12 '17 at 14:45

score 1 · Answer 2 · answered Sep 12 '17 at 14:39

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
    }
}

score 0 · Answer 3 · answered Sep 12 '17 at 14:42

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

Disallow words less than 3 characters

3 Answers3