F#扁平化嵌套元组 [英] F# flatten nested tuples

问题描述

是否可以在不显式映射F#的情况下展平F#中任意大小的元组?

is there a way to flatten tuples of arbitrary size in F# without explicitly mapping them?

(fun ((((a0,a1),a2),b),c) ->  (a0,a1,a2,b,c))

请注意，我从FParsec获得了这些元组，但是如果可以普遍使用的话，该功能将很方便.

As a note I'm getting these kind of tuples from FParsec but the capability would be convenient if it was available generally.

谢谢

推荐答案

您不容易做到，但经过一番思考，这是有可能的:

You can't do it easily, but with a bit of reflection it is possible:

let isTuple tuple =
    Microsoft.FSharp.Reflection.FSharpType.IsTuple(tuple.GetType()) 

let tupleValues (tuple : obj) = 
    Microsoft.FSharp.Reflection.FSharpValue.GetTupleFields tuple |> Array.toList

let rec flatten tupleFields =
    tupleFields |> List.collect(fun value ->
        match isTuple value with
        | true -> flatten (tupleValues value)
        | false -> [value]
    )

let tupleToList (tuple : obj) = 
    if isTuple tuple
        then Some (tupleValues tuple |> flatten)
        else None

例如，

let s = tupleToList ((100,101,102,103),1,2,3,(4,5))

会给您:

[100; 101; 102; 103; 1; 2; 3; 4; 5]

注意:此答案基于找到的代码这里.

NOTE: This answer is based on code found here.

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