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 = NSCharacterSet(charactersInString: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789") if (searchTerm!.rangeOfCharacterFromSet(characterSet).location == NSNotFound){     println("Could not handle special characters") } 

I tried the code above, but it matches only if I enter the first character as a special character.

Answer 1

Your code check if no character in the string is from the given set. What you want is to check if any character is not in the given set:

if (searchTerm!.rangeOfCharacterFromSet(characterSet.invertedSet).location != NSNotFound){     println("Could not handle special characters") } 

You can also achieve this using regular expressions:

let regex = NSRegularExpression(pattern: ".*[^A-Za-z0-9].*", options: nil, error: nil)! if regex.firstMatchInString(searchTerm!, options: nil, range: NSMakeRange(0, searchTerm!.length)) != nil {     println("could not handle special characters")  } 

The pattern [^A-Za-z0-9] matches a character which is not from the ranges A-Z, a-z, or 0-9.

Update for Swift 2:

let searchTerm = "a+b"  let characterset = NSCharacterSet(charactersInString: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789") if searchTerm.rangeOfCharacterFromSet(characterset.invertedSet) != nil {     print("string contains special characters") } 

Update for Swift 3:

let characterset = CharacterSet(charactersIn: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789") if searchTerm.rangeOfCharacter(from: characterset.inverted) != nil {     print("string contains special characters") }