Swift error when trying to access Dictionary: `Could not find member 'subscript'`

Question

This won\'t compile: I\'ve tried a couple different things; different ways of declaring th

Answer 1

func valueForCurrency(currency :String, exchange :String) -> Float? {
    if let exchanges = response["current_rates"] as? Dictionary {
        if let currencies = exchanges[exchange] as? Dictionary {
            return currencies[currency] as? Float
        }
    }
    return nil
}