C# のスレにあったサンプルを Swiftで書いてみた。 基本的には同じだが、Swiftの方が楽。

//------------ C#  (空白は全角を使っている)
class Program
{
  static void Main(string[] args)
  {
    var list = new List<Tuple<int, string>>();

    list.Add(Tuple.Create(31, "Jan"));
    list.Add(Tuple.Create(28, "Feb"));
    list.Add(Tuple.Create(31, "Mar"));
    list.Add(Tuple.Create(30, "Apr"));
    list.Add(Tuple.Create(31, "May"));

    list.Sort((Tuple<int, string> t1, Tuple<int, string> t2) => (t2.Item1 - t1.Item1));

    foreach (var t in list)
    {
      Console.WriteLine("{0} {1}", t.Item1, t.Item2);
    }
  }
}
//--------- Swift
let lists:(days: Int , month: String)[] = [ (31, "Jan") , (28, "Feb") , (31, "Mar") , (30, "Apr") , (31, "May") ]
sort ( lists , { $0.days < $1.days } )
println( lists )

/* ---------- このSwiftの sort 部分は、次のようにも書ける
sort ( lists , { ( t1, t2 ) -> Bool in t1.days < t2.days } ) // 或は
sort ( lists , { t1, t2 in t1.days < t2.days } ) 
*/