F# 排序记录序列，其中值尚未分配给序列中的类型

Question

我正在尝试按每条记录中的第二个元素对记录序列进行排序。问题是这些不是一个值，而只是一个类型。我有一个函数，它 returns 基于类型的值。

这是我的：

type Suit = Spades | Clubs | Hearts | Diamonds
type Rank = Ace | Two | Three | Four | Five | Six | Seven | Eight | Nine | Ten | Jack | Queen | King
type Card = { suit: Suit; rank: Rank}

type Hand = Card seq

let cardValue(card:Card) = 
    if (card.rank = Ace) then 1
    elif (card.rank = Two) then 2
    elif (card.rank = Three) then 3
    elif (card.rank = Four) then 4
    elif (card.rank = Five) then 5
    elif (card.rank = Six) then 6
    elif (card.rank = Seven) then 7
    elif (card.rank = Eight) then 8
    elif (card.rank = Nine) then 9
    elif (card.rank = Ten) then 10
    elif (card.rank = Jack) then 10
    elif (card.rank = Queen) then 10
    elif (card.rank = King) then 10
    else 0

let sortHandByValue(hand:Hand) = 
......missing code here......

我想做的是按等级作为值对手牌进行排序。

例如手牌目前是：{{Hearts;三}; {黑桃;杰克}; {钻石;两个}}

它将对 Hand 进行排序，因此结果是：{{Diamonds;二}; {红心;三}; {黑桃;杰克}}

我试过 hand |> Seq.sort |>Seq.groupBy id |> Seq.map snd 但这不是按值排序，而是按字母顺序排序。

我无法更改任何类型，但我可以更改其他所有类型。任何想法将不胜感激，谢谢！

Answer 1

您需要稍微清理一下显示记录的代码，我将 Card 类型重写为元组和匹配函数。然后你需要做的就是通过管道输入 Seq.sortBy 或 Seq.sortByDescending（按升序排序）：

type Suit = Spades | Clubs | Hearts | Diamonds
type Rank = Ace | Two | Three | Four | Five | Six | Seven | Eight | Nine | Ten | Jack | Queen | King
type Card = Suit * Rank

type Hand = Card seq

let cardValue (card:Card) = 
    match card with 
    | _, Ace -> 1
    | _, Two -> 2
    | _, Three -> 3
    | _, Four -> 4
    | _, Five -> 5
    | _, Six -> 6
    | _, Seven -> 7
    | _, Eight -> 8
    | _, Nine -> 9
    | _, Ten | _, Jack | _, Queen | _, King -> 10


let hand = seq [(Hearts, Three); (Spades, Jack); (Diamonds, Two)]

hand |> Seq.sortBy cardValue 
//val it : seq<Suit * Rank> =
//seq [(Diamonds, Two); (Hearts, Three); (Spades, Jack)]

有记录的版本： 我把它保持在你原来的位置。

/// Version with Records
type Suit = Spades | Clubs | Hearts | Diamonds
type Rank = Ace | Two | Three | Four | Five | Six | Seven | Eight | Nine | Ten | Jack | Queen | King
type Card = { suit: Suit; rank: Rank}
type Hand = seq<Card>

let cardValue(card:Card) = 
    if (card.rank = Ace) then 1
    elif (card.rank = Two) then 2
    elif (card.rank = Three) then 3
    elif (card.rank = Four) then 4
    elif (card.rank = Five) then 5
    elif (card.rank = Six) then 6
    elif (card.rank = Seven) then 7
    elif (card.rank = Eight) then 8
    elif (card.rank = Nine) then 9
    elif (card.rank = Ten) then 10
    elif (card.rank = Jack) then 10
    elif (card.rank = Queen) then 10
    elif (card.rank = King) then 10
    else 0

let hand = seq [{suit=Hearts; rank=Three}; {suit=Spades;rank=Jack}; {suit=Diamonds;rank= Two}]

hand |> Seq.sortBy cardValue

val it : seq = seq [{suit = Diamonds; rank = Two;}; {suit = Hearts; rank = Three;}; {suit = Spades; rank = Jack;}]

F# 排序记录序列，其中值尚未分配给序列中的类型

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