dictionary - 在 fsharp 中交换映射中的键和值

Question

如何创建一个与原始 map 类似但在 Fsharp 中交换键和值的新 map ？
例如，我有这个

let map1 =
[("A", "1"); ("B", "2"); ("C", "3");]
|> Map.ofList

并想得到这个:

let map2 =
[("1", "A"); ("2", "B"); ("3", "C");]
|> Map.ofList

感谢您的帮助!

Answer 1

也许你会接近这个决定:

let map1 = Map.ofList [("A", "1"); ("B", "2"); ("C", "3")]

map1 |> printfn "%A"

let rev map: Map<string,string> = 
      Map.fold (fun m key value -> m.Add(value,key)) Map.empty map

rev map1 |> printfn "%A"

打印:

map [("A", "1"); ("B", "2"); ("C", "3")]
map [("1", "A"); ("2", "B"); ("3", "C")]

链接:http://ideone.com/cfN2yH