How to check an object belonging to a class or structure in swift

Question

I was quickly stuck on this issue. Suppose I have one object, how to check if it is from a struct or class in swift.

Answer 1

In Swift 3.0, you can call Mirror(reflecting:x).displayStyle , where x is your value of interest. The result will be class , struct , enum , dictionary , set ... see the documentation https://developer.apple.com/reference/swift/mirror.displaystyle

Code example:

 struct SomeStruct { var name: String init(name: String) { self.name = name } } var astruct = SomeStruct(name:"myname") Mirror(reflecting:astruct).displayStyle == .struct // will be true Mirror(reflecting:astruct).displayStyle == .class; // will be false class MyClass { var name:String init(name: String) { self.name=name } } var aclass = MyClass(name:"fsdfd") Mirror(reflecting:aclass).displayStyle == .struct // will be false Mirror(reflecting:aclass).displayStyle == .class // will be true 

Of course, it would be best to handle using the switch-case statement in practice.

Answer 2

This approach works for me in Swift 3:

 class TestClass { } struct TestStruct { } var mystery:Any mystery = TestClass() // Is mystery instance a class type? print(type(of:mystery) is AnyClass ? "YES" : "NO") // prints: "YES" mystery = TestStruct() // Is mystery instance a class type? print(type(of:mystery) is AnyClass ? "YES" : "NO") // prints: "NO" 

Note that this approach tells you only if the instance is a class type or not. The fact that it is not a class does not necessarily mean its structure (there may be an enumeration, closure, tuple, etc.). But for most purposes and contexts, it’s enough to know if you are dealing with a reference type or value, a type that is usually needed.

Answer 3

There is an is operator.

 if someInstance is SomeType { // do something } 

And is there an as? operator as? .

 if let someInstance = someInstance as? SomeType { // now someInstance is SomeType } 

Answer 4

In swift4, checking a class or structure

 class TClass {} struct TStruct {} func who(_ any: Any) -> String { if Mirror(reflecting: any).displayStyle == .class { return "Class" } else { return "Struct" } } print(who("Hello")) // Struct print(who(TClass())) // Class print(who(TStruct())) // Struct print(who(1)) // Struct 

Answer 5

You can do this below, and for more information about this, please follow this link .

 class Shape { class func className() -> String { return "Shape" } } class Square: Shape { override class func className() -> String { return "Square" } } class Circle: Shape { override class func className() -> String { return "Circle" } } func getShape() -> Shape { return Square() // hardcoded for example } let newShape: Shape = getShape() newShape is Square // true newShape is Circle // false newShape.dynamicType.className() // "Square" newShape.dynamicType.className() == Square.className() 

Answer 6

A simple example:

  var name = "Big Hero" if name.isKindOfClass(NSString){ println("this is this class") }else{ println("this is not this class") }