在F#中将seq <string>转换为string []

Question

从这个例子这篇文章有一个例子

open System.IO

let lines = 
  File.ReadAllLines("tclscript.do")
  |> Seq.map (fun line ->
      let newLine = line.Replace("{", "{{").Replace("}", "}}")
      newLine )

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

编译时出错.

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

如何将seq转换为string []以删除此错误消息？

Answer 1

基于Jaime的答案,因为ReadAllLines()返回一个数组,只需使用Array.map而不是Seq.map

open System.IO

let lines = 
  File.ReadAllLines("tclscript.do")
  |> Array.map (fun line ->
      let newLine = line.Replace("{", "{{").Replace("}", "}}")
      newLine )

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

Answer 2

您可以使用

File.WriteAllLines("tclscript.txt", Seq.toArray lines)

或者只是附上

|> Seq.toArray

在Seq.map调用之后.

(另请注意,在.NET 4中,WriteAllLines的重载确实占用了Seq)