将Haskell GHCi命令结果输出到一个txt文件 [英] Outputting Haskell GHCi command results to a txt file

问题描述

我是Haskell的新手。

我很难将GHCi的命令结果输出到文件中。我想知道如果有人能给我一个关于如何做到这一点的简单解释？我迄今在网上找到的例子似乎过于复杂。

解决方案

假设您有一个函数 mungeData p>

  ghci> mungeData [1..5] 
 [5,2,5,2,4,6,7,4,6​​,78,4,7,5,3,57,7,4,6​​7,4， 6,7,4,6​​7,4] 
  

writeFile

您可以这样写入文件：

  ghci> writeFilemyoutput.txt（show（mungeData [1..5]）
  

我会倾向于写入

  ghci> writeFilemyoutput.txt$ show $ mungeData [1..5] 
  

除去一些括号。

读回来in

您可以使用

  ghci> fmap（ read :: String  - > [Int]）$ readFilemyoutput.txt
  

line

你可以像这样输出一行数字：

  ghci> writeFilemyoutput'.txt$ unlines.map show $ mungeData [1..5] 
  

  ghci> fmap（map read.lines :: String  - > [Int]）$ readFilemyoutput'.txt
  

I am new to Haskell.

I am having a really difficult time outputting command results from GHCi to a file. I was wondering if someone can give me a simple explanation on how to do this? The examples I have found online so far seem over complicated.

解决方案

Let's suppose you have a function mungeData and you do

 ghci> mungeData [1..5]
 [5,2,5,2,4,6,7,4,6,78,4,7,5,3,57,7,4,67,4,6,7,4,67,4]

writeFile

You can write this to file like this:

ghci> writeFile "myoutput.txt" (show (mungeData [1..5])

I'd be inclined to write

ghci> writeFile "myoutput.txt" $ show $ mungeData [1..5]

to get rid of a few brackets.

Reading it back in

You could get that back using

ghci> fmap (read::String -> [Int]) $ readFile "myoutput.txt"

One number per line

You could output it a line per number like this:

ghci> writeFile "myoutput'.txt" $ unlines.map show $ mungeData [1..5]

which reads back in as

ghci> fmap (map read.lines::String -> [Int]) $ readFile "myoutput'.txt"

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