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

You could do it this way:

var string = "Hello, World!"

if string.rangeOfString("W") != nil {
     println("exists")
} else {
     println("doesn't exist")
}

// alternative: not case sensitive
if string.lowercaseString.rangeOfString("w") != nil {
     println("exists")
} else {
     println("doesn't exist")
}