我可以在swift中有两种参数类型吗?

使用过载:

class Example
{
    func method(a : String) -> NSString {
    return a;
    }
    func method(a : UInt) -> NSString {
    return "{\(a)}"
    }
}

Example().method("Foo") // "Foo"
Example().method(123) // "{123}"

Javascript代码的等价物是:

func doSomething(parameter: Any?) {
    if let intValue = parameter as? Int {
       // do something with the int
    } else if let stringValue = parameter as? String {
      // do something with the string
    }
}

但请注意,这种方法会使您失去类型安全性,这是Swift最有用的特性之一。

更好的方法是声明一个协议,该协议由您希望传递给的所有类型实现 doSomething :

protocol MyProtocol {
    func doSomething()
}

extension Int: MyProtocol {
    func doSomething() {
        print("I am an int")
    }
}

extension String: MyProtocol {
    func doSomething() {
        print("I am a string")
    }
}

func doSomething(parameter: MyProtocol) {
    parameter.doSomething()
}


doSomething(1) // will print "I am an int"
doSomething("a") // will print "I am a string"
doSomething(14.0) // compiler error as Double does not conform to MyProtocol

它可以 示例代码:

func temFunc(obj:AnyObject){
    if let intValue = obj as? Int{
        print(intValue)
    }else if let str = obj as? String{
        print(str)
    }
}

你可以利用 Any 和向下播放:

func foo(bar: Any){
    switch(bar) {
    case let a as String:
        /* do something with String instance 'a' */
        print("The bar is a String, bar = " + a)
    case let a as Int:
        /* do something with Int instance 'a' */
        print("The bar is an Int, bar = \(a)")
    case _ : print("The bar is neither an Int nor a String, bar = \(bar)")
    }
}

/* Example */   
var myString = "Hello"
var myInt = 1
var myDouble = 1.5

foo(myString) // The bar is a String, bar = Hello
foo(myInt)    // The bar is an Int, bar = 1
foo(myDouble) // The bar is neither an Int nor a String, bar = 1.5

检查此解决方案:

https://stackoverflow.com/a/25528882/256738

你可以传递一个对象 AnyObject 并检查类以了解它是什么类型的对象。

更新

好点子@Vojtech Vrbka

这里有一个例子:

let x : AnyObject = "abc"
switch x {
  case is String: println("I'm a string")
  case is Array: println("I'm an Array")
  // Other cases
  default: println("Unknown")
}