小编Fie*_*nko的帖子

我遇到了这个问题:

Couldn't match expected type ‘Int’ with actual type ‘Maybe Int’

我可以以某种方式将'Maybe Int'转换为'Int'吗？

if index == Nothing 
   then 
     do 
       let index = 0
       putStrLn(fancyPrint2 $ kaasasOlevList !! index)
   else 
     do 
       let index = index
       putStrLn(fancyPrint2 $ kaasasOlevList !! index)

我试过这样,但这给了我:

Exception: <<loop>>