Haskell 语言 字符串处理与文本格式化实战

Haskell 语言字符串处理与文本格式化实战

Haskell 是一种纯函数式编程语言，以其强大的函数式编程特性和简洁的语法而闻名。在处理字符串和文本格式化方面，Haskell 提供了一系列高效且强大的工具和库。本文将围绕 Haskell 语言在字符串处理与文本格式化方面的实战，探讨一些常用的技术和方法。

字符串基础

在 Haskell 中，字符串被定义为字符序列，使用双引号 `"` 包围。以下是一些基本的字符串操作：

1. 字符串拼接

haskell
main :: IO ()

main = do

    let str1 = "Hello, "

    let str2 = "world!"

    let result = str1 ++ str2

    print result

2. 字符串长度

haskell
main :: IO ()

main = do

    let str = "Haskell"

    print $ length str

3. 字符串索引

haskell
main :: IO ()

main = do

    let str = "Haskell"

    print $ str !! 0

4. 字符串切片

haskell
main :: IO ()

main = do

    let str = "Haskell"

    print $ take 5 str

    print $ drop 5 str

    print $ take 5 $ drop 5 str

高级字符串操作

1. 字符串搜索

haskell
main :: IO ()

main = do

    let str = "The quick brown fox jumps over the lazy dog"

    print $ isPrefixOf "The " str

    print $ isSuffixOf "dog" str

    print $ isInfixOf "quick" str

2. 字符串替换

haskell
main :: IO ()

main = do

    let str = "Haskell is great"

    print $ replace "is" "was" str

3. 字符串分割与连接

haskell
main :: IO ()

main = do

    let str = "Haskell is great"

    let parts = words str

    print parts

    let result = unwords parts

    print result

文本格式化

文本格式化是字符串处理的一个重要方面。以下是一些常用的文本格式化技术：

1. 字符串填充

```haskell

main :: IO ()

main = do

let str = "Haskell"

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