Accessing an Enumeration Association Value in Swift

For sake of completeness, enum's association value could be accesed also using if statement with pattern matching. Here is solution for original code:

enum Number {
  case int (Int)
  case float (Float)
}

let integer = Number.int(10)
let float = Number.float(10.5)

if case let .int(i) = integer {
  print("integer is \(i)")
}
if case let .float(f) = float {
  print("float is \(f)")
}

This solution is described in detail in:

It surprises me that Swift 2 (as of beta 2) does not address this. Here's an example of a workaround approach for now:

enum TestAssociatedValue {
  case One(Int)
  case Two(String)
  case Three(AnyObject)

  func associatedValue() -> Any {
    switch self {
    case .One(let value):
      return value
    case .Two(let value):
      return value
    case .Three(let value):
      return value
    }
  }
}

let one = TestAssociatedValue.One(1)
let oneValue = one.associatedValue() // 1
let two = TestAssociatedValue.Two("two")
let twoValue = two.associatedValue() // two

class ThreeClass {
  let someValue = "Hello world!"
}

let three = TestMixed.Three(ThreeClass())
let threeValue = three. associatedValue() as! ThreeClass
print(threeValue.someValue)

If your enum mixes cases with and without associated values, you'll need to make the return type an optional. You could also return literals for some cases (that do not have associated values), mimicking raw-value typed enums. And you could even return the enum value itself for non-associated, non-raw-type cases. For example:

enum TestMixed {
  case One(Int)
  case Two(String)
  case Three(AnyObject)
  case Four
  case Five

  func value() -> Any? {
    switch self {
    case .One(let value):
      return value
    case .Two(let value):
      return value
    case .Three(let value):
      return value
    case .Four:
      return 4
    case .Five:
      return TestMixed.Five
    }
  }
}

let one = TestMixed.One(1)
let oneValue = one.value() // 1
let two = TestMixed.Two("two")
let twoValue = two.value() // two

class ThreeClass {
  let someValue = "Hello world!"
}

let three = TestMixed.Three(ThreeClass())
let threeValue = three.value() as! ThreeClass
print(threeValue.someValue)

let four = TestMixed.Four
let fourValue = four.value() // 4

let five = TestMixed.Five
let fiveValue = five.value() as! TestMixed

switch fiveValue {
case TestMixed.Five:
  print("It is")
default:
  print("It's not")
}
// Prints "It is"

You can access enum associated value not only through switch! Mirrors come to our aid

Let's create a protocol

protocol MirrorAssociated {
    var associatedValues: [String: Any] { get }
}

extension MirrorAssociated {
    var associatedValues: [String: Any] {
        var values = [String: Any]()
        if let associated = Mirror(reflecting: self).children.first {
            let children = Mirror(reflecting: associated.value).children
            for case let item in children {
                if let label = item.label {
                    values[label] = item.value
                }
            }
        }
        return values
    }
}

and use it like this:

enum Test: MirrorAssociated {
    case test(value: String, anotherValue: Int)
}

Now we can access any associated value without using switch:

let test: Test = .test(value: "Test String", anotherValue: 1337)

if let value = test.associatedValues["value"] as? String {
    print("\(value)") // "Test String"
}

if let intValue = test.associatedValues["anotherValue"] as? Int {
    print("\(intValue)") // 1337
}

I have used something like this:

switch number {
case .int(let n):
    println("integer is \(n)")
case .float(let n):
    println("float is \(n)")
}

like @iQ. answer, you can use property in enum also

enum Number {
    case int (Int)
    var value: Int {
        switch self {
            case .int(let value):
                return value
        }
    }
}

let integer = Number.int(10)
println("integer is \(integer.value)")

enum NumberEnum {
    case int(Int)
    case float(Float)
    case twoInts(Int, Int)
}

let someNum = NumberEnum.twoInts(10,10)

To get value from ValueAssociatedEnum you able to follow one of 3 ways:

Way 1:

if case .twoInts( let val1, let val2 ) = someNum {
    print("hello \(val1) \(val2)")
}