Swift学習ノートタイプ変換

class MediaItem {
    var name: String
    init(name: String){
        self.name = name
    }
}
class Movie: MediaItem {
    var director: String
    init(name: String,director: String) {
        self.director = director
        super.init(name: name)
    }
}
class Song: MediaItem {
    var artist: String
    init(name: String, artist: String) {
        self.artist = artist
        super.init(name: name)
    }
}
let library = [
    Movie(name: "Casablanca", director: "Michael curtiz"),
    Song(name: "Blue Suede Shoes", artist: "Elvis Presley"),
    Movie(name: "Citizen Kane", director: "Orson Welles"),
    Song(name: "The One And Only", artist: "Chesney Hawkes"),
    Song(name: "Never Gonna Give You Up", artist: "Rick Astley")
]

var movieCount = 0
var songCount = 0
for item in library {
    if item is Movie {
        ++movieCount
    } else if item is Song {
        ++songCount
    }
}
println("Media library contains \(movieCount) movies and \(songCount) songs")
for item in library {
    if let movie = item as? Movie {
        println("Movie: '\(movie.name)', dir. \(movie.director)")
    } else if let song = item as? Song {
         println("Song: '\(song.name)', by \(song.artist)")
    }
}

let someObjects: [AnyObject] = [
    Movie(name: "2001: ASpace Odyssey", director: "Stanley Kubrick"),
    Movie(name: "Moon", director: "Duncan Jones"),
    Movie(name: "Alien", director: "Ridley Scott")
]
for object in someObjects {
    let movie = object as! Movie
    println("Movie: '\(movie.name)', dir. \(movie.director)")
}

var things = [Any]()
things.append(0)
things.append(0.0)
things.append(42)
things.append(3.14159)
things.append("hello")
things.append((3.0,5.0))
things.append(Movie(name: "Ghostbusters", director: "Ivan Reitman"))

swiftのスーパークラスは2種類に分けられていることを覚えておいてください.1つはAnyObjectがすべてのクラスタイプを表すスーパークラスで、1つはAnyがすべてのタイプを表すスーパークラスです.
その他の変換、ネスト