元組作爲字典值

Question

我的問題是：我有一個枚舉類型爲鍵和名爲元組作爲值的字典。

private let positionDictionary:[Position:(shortG: String, longG: String, shortE: String, longE: String)] = 
[ .Goalkeeper:("TW","Torwart","GK","Goalkeeper"), 
    .CentralDefender:("IV","Innenverteidiger","CD","Central Defender"), 
    .LeftBack:("LV","Linker Verteidiger","LB","Left Back"), 
    .LeftWingBack:("LAV","Linker Außenverteidiger","LWB","Left Wing Back"), 
    .RightBack:("RV","Rechter Verteidiger","RB","Right Back"), 
    .RightWingBack:("RAV","Rechter Außenverteidiger","RWB","Right Wing Back")] 

這就是我想要做的這個類的一部分：

self.positionDictionary[.Goalkeeper].shortE 

但是，編譯器告訴我，他「找不到成員‘shortE’」。我錯過了什麼？我真的很感激任何幫助：]

Answer 1

字典鍵下標返回可選值。你需要解開，或使用可選的招標：

if let goalkeepersShortE = self.positionDictionary[.Goalkeeper]?.shortE { 
    // ... 
}