在haskell中删除词语

Question

我是Haskell的新手和功能编程..

我的目标是从用户那里获取一个字符串,并检查该字符串中是否有可用的词干.如果是这样我想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到这一点.但我不知道如何在Haskell中做到这一点.做任何人都知道如何使用Haskell解决这个问题..

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

我试过,但我知道错了.任何人都可以帮我解决这个问题,请...

Answer 1

一次解决一个词,这使事情变得更容易:

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isSuffixOffrom Data.List:

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