How to check two instances are the same class/type in swift

I also answered How do you find out the type of an object (in Swift)? to point out that at some point Apple added support for the === operator to Swift Types, so the following will now work:

if item1.dynamicType === item2.dynamicType {
    print("Same subclass")
} else {
    print("Different subclass")
}

This works even without importing Foundation, but note it will only work for classes, as structs have no dynamic type.

Swift 3.0 (also works with structs)

if type(of: someInstance) == type(of: anotherInstance) {
    print("matching type")
} else {
    print("something else")
}

I feel necessary to quote from the Swift Programming Language documentation first of all:

Classes have additional capabilities that structures do not:

• Type casting enables you to check and interpret the type of a class instance at runtime.

According to this, it may be helpful for someone in the future:

func areTheySiblings(class1: AnyObject!, class2: AnyObject!) -> Bool {
    return object_getClassName(class1) == object_getClassName(class2)
}

and the tests:

let myArray1: Array<AnyObject> = Array()
let myArray2: Array<Int> = Array()
let myDictionary: Dictionary<String, Int> = Dictionary()
let myString: String = String()

let arrayAndArray: Bool = self.areTheySiblings(myArray1, class2: myArray2) // true
let arrayAndString: Bool = self.areTheySiblings(myArray1, class2: myString) // false
let arrayAndDictionary: Bool = self.areTheySiblings(myArray1, class2: myDictionary) // false

UPDATE

you also can overload a new operator for doing such a thing, like e.g. this:

infix operator >!<

func >!< (object1: AnyObject!, object2: AnyObject!) -> Bool {
   return (object_getClassName(object1) == object_getClassName(object2))
}

and the results:

println("Array vs Array: \(myArray1 >!< myArray2)") // true
println("Array vs. String: \(myArray1 >!< myString)") // false
println("Array vs. Dictionary: \(myArray1 >!< myDictionary)") // false

UPDATE#2

you can also use it for your own new Swift classes, like e.g. those:

class A { }
class B { }

let a1 = A(), a2 = A(), b = B()

println("a1 vs. a2: \(a1 >!< a2)") // true
println("a1 vs. b: \(a1 >!< b)") // false

Swift 3 - pay attention that comparing instances is not the same as checking if an istance is of a given type:

struct Model {}

let modelLhs = Model()
let modelRhs = Model()
type(of: modelLhs) == type(of: modelRhs) //true
type(of: modelLhs) == type(of: Model.self) //false
modelLhs is Model //true