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

我的运气是:

let className = NSStringFromClass(obj.dynamicType)

其他回答

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。

Xcode 7.3.1, Swift 2.2:

字符串(instanceToPrint.self) .componentsSeparatedByString .last(“。”)

这就是你要找的吗?

println("\(object_getClassName(now))");

它输出__NSDate

更新:请注意,这似乎不再工作Beta05

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" {
    ...
}

Swift 3.0, Xcode 8

使用下面的代码,您可以向实例请求其类。你也可以比较两个实例,是否具有相同的类。

// CREATE pure SWIFT class
class MySwiftClass {
    var someString : String = "default"
    var someInt    : Int = 5
}

// CREATE instances
let firstInstance = MySwiftClass()
let secondInstance = MySwiftClass()
secondInstance.someString = "Donald"
secondInstance.someInt = 24

// INSPECT instances
if type(of: firstInstance) === MySwiftClass.self {
    print("SUCCESS with ===")
} else {
    print("PROBLEM with ===")
}

if type(of: firstInstance) == MySwiftClass.self {
    print("SUCCESS with ==")
} else {
    print("PROBLEM with ==")
}

// COMPARE CLASS OF TWO INSTANCES
if type(of: firstInstance) === type(of: secondInstance) {
    print("instances have equal class")
} else {
    print("instances have NOT equal class")
}