对列表中的每个元素应用函数

Question

我创建了一个函数m，这样

m "abc" "def" == "bcd" 

我想创建另一个函数，用于在给定输入时m生成输出["bcd","efg","hia"]["abc","def","ghi"]

的定义m是

m :: [a] -> [a] -> [a]
m str1 str2 = (drop 1 str1) ++ (take 1 str2)

Answer 1

您可以使用zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]此处将整个列表作为第一个参数和tail (cycle l)第二个参数（带有l列表）：

combine :: [a] -> [a]
combine l = zipWith m l (tail (cycle l))

zipWith将同时枚举两个列表，并且每次调用m第一个和第二个列表的元素。例如：

Prelude> combine ["abc","def","ghi"]
["bcd","efg","hia"]