string - F# 中的绝对初学者 - 需要帮助

Question

我有以下代码 -

let items = [
    (20,"cat");
    (13,"can");
    (19,"letter");
    (55,"dog");
    (87,"kettle");
    (122,"weight");
]

有人可以给我举个例子，给出编号为 13 的项目名称吗？我尝试的一切都返回错误，在网上查找了一些示例，但没有一个！

注意 - 以前的解决方案不起作用。执行此操作的最简单方法是什么？

Answer 1

let getName people id =
    people 
    |> Seq.filter (fun person -> fst person = id)
    |> Seq.head
    |> snd

    // or: |> Seq.filter (fst >> (=) id)

let getId people name =
    people 
    |> Seq.filter (fun person -> snd person = name)
    |> Seq.head
    |> fst

let getNames people =
    people
    |> List.map snd

您可以按如下方式调用它们：

printfn "%d" (getId people "LIAM")
printfn "%s" (getName people 44567)
printfn "%A" (getNames people)