Check if string contains special characters in Swift

Question

I have to detect whether a string contains any special characters. How can I check it? Does Swift support regular expressions?

var characterSet:NSCharacterSet         


        

Answer 1

For the purpose of filename sanitization, I prefer to detect the invalid characters, rather than provide an allowed character set. After all, many non-English speaking users need accented characters. The following function is inspired by this gist:

func checkForIllegalCharacters(string: String) -> Bool {
    let invalidCharacters = CharacterSet(charactersIn: "\\/:*?\"<>|")
    .union(.newlines)
    .union(.illegalCharacters)
    .union(.controlCharacters)

    if string.rangeOfCharacter(from: invalidCharacters) != nil {
        print ("Illegal characters detected in file name")
        // Raise an alert here
        return true
    } else {
    return false
}