What is the best way to determine if a string contains a character from a set in Swift

Question

I need to determine if a string contains any of the characters from a custom set that I have defined.

I see from this post that you can use rangeOfString to determine

Answer 1

ONE LINE Swift4 solution to check if contains letters:

CharacterSet.letters.isSuperset(of: CharacterSet(charactersIn: myString) // returns BOOL

Another case when you need to validate string for custom char sets. For example if string contains only letters and (for example) dashes and spaces:

let customSet: CharacterSet = [" ", "-"]
let finalSet = CharacterSet.letters.union(customSet)
finalSet.isSuperset(of: CharacterSet(charactersIn: myString)) // BOOL

Hope it helps someone one day:)