「再帰関数を Collections.Seq 系関数に書き換える」ブログ用

UseTakeWhile.fs

open System

let rec loop () =
    let line = Console.ReadLine()
    if line <> null then
        let numericStr =
            line
            |> Seq.takeWhile(fun s -> Char.IsNumber(s))
            |> Seq.toArray
        Console.WriteLine(numericStr)
        loop ()

loop ()

UseTryFindIndex.fs

open System

let rec loop () =
    let line = Console.ReadLine()
    if line <> null then
        let notNumIndex = line |> Seq.tryFindIndex(fun s -> not(Char.IsNumber(s)))
        match notNumIndex with
            | Some (n) -> Console.WriteLine(line.[0 .. n - 1])
            | None -> Console.WriteLine(line)
        loop ()

loop ()