Get nth character of a string in Swift programming language

Question

How can I get the nth character of a string? I tried bracket([]) accessor with no luck.

var string = \"Hello, world!\"

var firstChar = string[         


        

Answer 1

Update for swift 2.0 subString

public extension String {
    public subscript (i: Int) -> String {
        return self.substringWithRange(self.startIndex..) -> String {
        get {
            return self.substringWithRange(self.startIndex.advancedBy(r.startIndex)..