haskell从列表列表中删除所有出现的给定值

Question

我想从列表列表中删除所有出现的给定值.例如,输入:

'a' ["abc", "bc", "aa"] 

输出:

 ["bc", "bc", ""]

至今:

remove :: Eq a => a -> [[a ]] -> [[a ]]
remove y xs = filter(\x -> x/= y) xs

我收到了错误,请提前谢谢.

Answer 1

您需要映射外部列表.

remove y xs = map (filter(\x -> x/= y)) xs

你实际上不需要lambda,更好:

remove y xs = map (filter(/=y)) xs