//MARK:----------字典-------------- /* 字典(key : value)*/ //如果类型信息已知,使用[:]声明空字典。 let emptyDictionary1 = [:] let emptyDictionary2 = Dictionary<String,Float>() let emptyDictionary3 = [String: Float]() print(emptyDictionary2.count) //var airports: Dictionary<String,String> = ["TYO": "Tokyo","dub": "dublin"] var airportsDic = ["TYO": "Tokyo","dub": "dublin"] print(airportsDic["TYO"]) //---------添加---------- airportsDic["LHR"] = "London" print(airportsDic) //-------修改------ airportsDic["LHR"] = "London Heathrow" // the value for "LHR" has been changed to "London Heathrow print(airportsDic) //等价于 //airports.updateValue("dublin International",forKey: "dub") //print(airports) //------------删除----------- airportsDic["LHR"] = nil print(airportsDic) //等价于 //airportsDic("dub") //print(airportsDic) //---------查询---------- print("字典元素个数为" + String(airportsDic.count)) print("字典包含 \(airportsDic.count) 个元素.") print(airportsDic.startIndex) print(airportsDic.endindex) //-------------遍历字典----------- for (key,Value) in airportsDic { print("\(key): \(Value)") } for key in airportsDic.keys { print("Airport code: \(key)") } for Value in airportsDic.values { print("Airport name: \(Value)") } let airportKeys = Array(airportsDic.keys) // airportCodes is ["TYO","LHR"] let airportValues = Array(airportsDic.values) // airportNames is ["Tokyo","London Heathrow"] print(airportKeys) print(airportValues)