Haskell - 将包含数字的文件读入列表 [英] Haskell - Read a file containing numbers into a list

问题描述

所以我有一个这种格式的文本文件：

So I have a text file in this format:

1 3 4 5 1 3 9 12 5

假设此文件名为 numbers.txt 。

我想告诉Haskell从文件中读取，并将这些数字放在列表中。所以我最终得到：

I want to tell Haskell to read from the file, and put those numbers in a list. So I would end up with:

[1,3,4,5,1,3,9,12,5]

我真的不明白怎么做，而且我一直在搜索。我知道我需要使用getLine，但那又怎么样？我会使用函数将该字符串映射到列表吗？我真的不确定如何写这个，我知道这可能是一个非常愚蠢的问题，但我刚开始学习Haskell，我想继续前进。

I really don't understand how to do this, and I've been searching a lot. I know I'll need to use getLine, but then what? Would I use a function to map that string to a list? I'm really not sure how I would write this, and I know it's probably a really stupid question, but I just started learning Haskell and I want to go forward.

推荐答案

在这么多行......

In so many lines...

getNumbers :: String -> [Int]
getNumbers str = -- left as exercise
                 -- helpful functions: `read`, `words`

main :: IO ()
main = do
    contents <- readFile "numbers.txt"
    let numbers = getNumbers contents
    print numbers

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