Swift - Case語句和MetaType檢查？

Question

鑑於字典，我需要檢查值是字典，數組或其他。 我得到以下錯誤：

Downcast pattern value of type Dictionary cannot be used

// Type of dictionary to enumerate through 
public typealias SourceDictionary = [String: AnyObject] 
var dictionary: SourceDictionary 


for (key, value) in dictionary { 
    switch (value) { 
     case value as SourceDictionary : 
     print("Dictionary") 

     case value as Array : 
     print("Array") 

     default : 
     print("Other") 
    } 
} 

也試過

case let someValue as SourceDictionary 

Answer 1

您可與一個switch或if語句檢查，你的語法僅僅是不完全正確。

開關：

for (key, value) in dictionary { 
    switch value { 
    case let v as Dictionary<String, AnyObject>: 
     println("Dictionary in \(key)") 
    default: 
     println("other") 
    } 
} 

如果：

for (key, value) in dictionary { 
    if let v = value as? Dictionary<String, AnyObject> { 
     println("Dictionary in \(key)") 
    } 
}