是否有一种方法可以在swift中打印变量的运行时类型?例如:
var now = NSDate()
var soon = now.dateByAddingTimeInterval(5.0)
println("\(now.dynamicType)")
// Prints "(Metatype)"
println("\(now.dynamicType.description()")
// Prints "__NSDate" since objective-c Class objects have a "description" selector
println("\(soon.dynamicType.description()")
// Compile-time error since ImplicitlyUnwrappedOptional<NSDate> has no "description" method
在上面的例子中，我正在寻找一种方法来显示变量“soon”的类型是ImplicitlyUnwrappedOptional<NSDate>，或至少NSDate!
当前回答
这在检查一个对象是否是类的类型时也很方便:
if someObject is SomeClass {
//someObject is a type of SomeClass
}
其他回答
斯威夫特3.0
let string = "Hello"
let stringArray = ["one", "two"]
let dictionary = ["key": 2]
print(type(of: string)) // "String"
// Get type name as a string
String(describing: type(of: string)) // "String"
String(describing: type(of: stringArray)) // "Array<String>"
String(describing: type(of: dictionary)) // "Dictionary<String, Int>"
// Get full type as a string
String(reflecting: type(of: string)) // "Swift.String"
String(reflecting: type(of: stringArray)) // "Swift.Array<Swift.String>"
String(reflecting: type(of: dictionary)) // "Swift.Dictionary<Swift.String, Swift.Int>"
斯威夫特4:
// "TypeName"
func stringType(of some: Any) -> String {
let string = (some is Any.Type) ? String(describing: some) : String(describing: type(of: some))
return string
}
// "ModuleName.TypeName"
func fullStringType(of some: Any) -> String {
let string = (some is Any.Type) ? String(reflecting: some) : String(reflecting: type(of: some))
return string
}
用法:
print(stringType(of: SomeClass())) // "SomeClass"
print(stringType(of: SomeClass.self)) // "SomeClass"
print(stringType(of: String())) // "String"
print(fullStringType(of: String())) // "Swift.String"
不完全是你想要的，但你也可以检查Swift类型的变量类型，像这样:
let object: AnyObject = 1
if object is Int {
}
else if object is String {
}
为例。
在最新的XCode 6.3和Swift 1.2中，这是我发现的唯一方法:
if view.classForCoder.description() == "UISegment" {
...
}
我在这里尝试了一些其他的答案，但milage似乎很清楚下面的对象是什么。
然而，我确实发现了一种方法，你可以通过以下方式获得对象的object - c类名:
now?.superclass as AnyObject! //replace now with the object you are trying to get the class name for
下面是一个如何使用它的例子:
let now = NSDate()
println("what is this = \(now?.superclass as AnyObject!)")
在本例中，它将在控制台中打印NSDate。
