haskell中词干词条的删除

Question

我对Haskell和函数式编程很陌生。

我的目标是从用户那里获得一个字符串，并检查该字符串中是否有任何词干词根可用。如果是这样的话，我希望删除词干并返回字符串。

Eg: if input is :"He is fishing and catching"
    output is : "he is fish and catch"

我可以用其他语言做这件事。但我不知道在Haskell该怎么做。有人知道如何用Haskell解决这个问题吗。

checkstemming :: [String] -> [String]
checkstemming [] = []
checkstemming xs = foldr (++) [] ( [ drop x |x <- xs, x="ing"])

我试过了，但我知道这是错误的。有人能帮我解决这个问题吗？

Answer 1

一次只处理一个词，这会使事情变得容易得多：

removeStemming :: String -> String
removeStemming []        = []
removeStemming (x:"ing") = [x]
removeStemming (x:xs)    = x : removeStemming xs

checkStemming :: [String] -> [String]
checkStemming = map removeStemming

另一种方法是使用来自Data.List的Data.List

removeStemming :: String -> String
removeStemming xs
  | "ing" `isSuffixOf` xs = take (length xs - 3) xs
  | otherwise             = xs