Type Casting for Any & AnyObject in Swift

Written by Team Kodeco

Any and AnyObject are two special type aliases in Swift that allow you to cast any value to a specific type.

Any is used to represent any type, including functions and optional types, whereas AnyObject is used to represent any instance of a class type.

Here’s an example using Any:

let mixedArray: [Any] = [1, "Hello", true, 2.0]
for item in mixedArray {
  switch item {
  case let x as Int:
    print("Int: \(x)")
  case let x as String:
    print("String: \(x)")
  case let x as Bool:
    print("Bool: \(x)")
  case let x as Double:
    print("Double: \(x)")
  default:
    print("Unknown type")
  }
}

In this example, an array mixedArray is defined with elements of various types, including Int, String, Bool, and Double. The for loop iterates over the elements of the array and uses a switch statement to perform type casting and determine the type of each element.

Here’s an example using AnyObject:

class Car {}
class Song {}

let objectsArray: [AnyObject] = [Car(), Car(), Song()]
for item in objectsArray {
  if let car = item as? Car {
    print("Car: \(car)")
  } else if let song = item as? Song {
    print("Song: \(song)")
  } else {
    print("Unknown type")
  }
}

In this example, an array objectsArray is defined with elements of class types, including Car and Song. The for loop iterates over the elements of the array and uses as? operator to perform type casting and determine the type of each element. If the type cast is successful, the appropriate message is printed.

Difference Between Any and AnyObject

Any is a type in Swift that can represent an instance of any type, including function types. It can be used to store heterogeneous collections of values.

AnyObject is a type in Swift that can represent an instance of any class type. It can be used to store collections of class instances where the specific class type is unknown.

The main difference between Any and AnyObject is that Any can represent any type, including value types and function types, while AnyObject can only represent class types.