Question

我正在解析HTML（通过HAP），现在正在解析每行的特定表列内容（TD元素的集合）

注意：不使用FSharp.Data的HTML解析器，因为它与包含<Script>代码的html损坏，导致CSS选择器失败（已知问题）

我尝试将一行数据映射到的类型（10个不同类型的“列”）：

type DailyRow = { C0: string; C1: string; C2: int; C3: decimal; C4: string; C5: string; C6: int; C7: decimal; C8: decimal; C9: int }

我难看但有效的函数将列位置映射到记录字段中（是的，任何无法正确解析的东西都会爆炸）：

let dailyRow = fun (record:DailyRow, column:int, node:HtmlNode) ->
        printfn "dailyRow: Column %i has value %s" column node.InnerText
        match column with 
        | 0 -> {record with C0 = node.InnerText }
        | 1 -> {record with C1 = node.InnerText }
        | 2 -> {record with C2 = (node.InnerText |> int) }
        | 3 -> {record with C3 = Decimal.Parse(node.InnerText, NumberStyles.Currency) }
        | 4 -> {record with C4 = node.InnerText }
        | 5 -> {record with C5 = node.InnerText }
        | 6 -> {record with C6 = Int32.Parse(node.InnerText, NumberStyles.AllowThousands) }
        | 7 -> {record with C7 = Decimal.Parse(node.InnerText, NumberStyles.Currency) }
        | 8 -> {record with C8 = Decimal.Parse(node.InnerText, NumberStyles.Currency) }
        | 9 -> {record with C9 = (node.InnerText |> int) }
        | _ -> raise (System.MissingFieldException("New Field in Chart Data Found: " + column.ToString()))

一些测试代码：

let chartRow = { C0 = ""; C1 = ""; C2 = 0; C3 = 0.0M; C4 = "" ; C5 = ""; C6 = 0; C7 = 0.0M; C8 = 0.0M; C9 = 0 }
let columnsToParse = row.SelectNodes "td" // 1 row of 10 columns
let x = columnsToParse
                |> Seq.mapi (fun i x -> dailyRow(chartRow, i, x))

问题是，由于我要传递不可变的记录并通过Seq.mapi从dailyRow函数接收新记录（使用索引映射到列号），因此我将得到10条记录，每条记录设置了其中一组values属性。

在C＃中，我只需传递dailyRow一个ref'd对象并将其更新到位，F＃惯用的处理方式是什么？

Answer 1

最简单的选择，如果您不介意数组分配：

let nodes = seq [...]
let arr = nodes |> Seq.map (fun n -> n.InnerText) |> Array.ofSeq
let record = 
    { C0 = arr.[0]
      C1 = arr.[1]
      C2 = int arr.[2]
      C3 = Decimal.Parse(arr.[3], NumberStyles.Currency)
      C4 = arr.[4]
      C5 = arr.[5]
      C6 = Int32.Parse(arr.[6], NumberStyles.AllowThousands)
      C7 = Decimal.Parse(arr.[7], NumberStyles.Currency)
      C8 = Decimal.Parse(arr.[8], NumberStyles.Currency)
      C9 = int arr.[9] }

将集合/序列投影到单个记录中

1 个答案: