Swiftでのタイプ変換
1521 ワード
タイプ変換
is
およびas
.チェックの種類
someInstance
is
someClass ダウンコンバート
optional form:
as?
force form: as
AnyとAnyObject
AnyObject
、classタイプのインスタンスAny
、任意のタイプのインスタンス(関数タイプを除く)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"))
for thing in things {
switch thing {
case 0 as Int:
println("zero as an Int")
case 0 as Double:
println("zero as a Double")
case let someInt as Int:
println("an integer value of \(someInt)")
case let someDouble as Double where someDouble > 0:
println("a positive double value of \(someDouble)")
case is Double:
println("some other double value that I don't want to print")
case let someString as String:
println("a string value of \"\(someString)\"")
case let (x, y) as (Double, Double):
println("an (x, y) point at \(x), \(y)")
case let movie as Movie:
println("a movie called '\(movie.name)', dir. \(movie.director)")
default:
println("something else")
}
}
switch
のコンテキストでforce formを使用するas
は安全です.