string - F# 将字符串数组转换为字符串

Question

使用 C#，我可以使用 string.Join("", lines)将字符串数组转换为字符串。
我能做些什么来用 F# 做同样的事情？

添加

我需要从文件中读取行，执行一些操作，然后将所有行连接成一行。

当我运行此代码时

open System.IO
open String

let lines = 
  let re = System.Text.RegularExpressions.Regex(@"#(\d+)")
  [|for line in File.ReadAllLines("tclscript.do") ->
      re.Replace(line.Replace("{", "{{").Replace("}", "}}").Trim(), "$1", 1)|]

let concatenatedLine = String.Join("", lines)

File.WriteAllLines("tclscript.txt", concatenatedLine)

我收到这个错误

error FS0039: The value or constructor 'Join' is not defined

我试过这个代码 let concatenatedLine = lines |> String.concat ""得到这个错误

error FS0001: This expression was expected to have type
    string []    
but here has type
    string

解决方案

open System.IO
open System 

let lines = 
  let re = System.Text.RegularExpressions.Regex(@"#(\d+)")
  [|for line in File.ReadAllLines("tclscript.do") ->
      re.Replace(line.Replace("{", "{{").Replace("}", "}}"), "$1", 1) + @"\n"|]

let concatenatedLine = String.Join("", lines)
File.WriteAllText("tclscript.txt", concatenatedLine)

这个也有效。

let concatenatedLine = lines |> String.concat ""

Answer 1

使用 String.concat 吗？

["a"; "b"]
|> String.concat ", " // "a, b"

编辑:

在你的代码中用 File.WriteAllText 替换 File.WriteAllLines

let concatenatedLine = 
    ["a"; "b"]
    |> String.concat ", "

open System.IO

let path = @"..."
File.WriteAllText(path, concatenatedLine)