相关疑难解决方法(0)

如何在函数式编程语言中增加变量？

例如,我想这样做:

main :: IO ()
main = do
    let i = 0
    i = i + 1
    print i

预期产量:1.

我想从列表中删除一个项目，但它又回来了。

main = do
  let y = ["aa","bb","cc","dd","ee","ff"]
  let n = length y
  replicateM_ (n-1) (deleteWord y)

deleteWord y = do
  putStrLn "Write a word: "
  word <- getLine
  let new_y = delete word y
  print new_y

输出：

*Main> main
Write a word: 
aa
["bb","cc","dd","ee","ff"]
Write a word: 
bb
["aa","cc","dd","ee","ff"]
Write a word: 
cc
["aa","bb","dd","ee","ff"]

我希望 和"aa"保持"bb"删除状态，并且不再回到列表中。