如何在haskell中连接两个列表

Question

我有两个列表x = ["a","b","c"]和y = ["Argentina","Brazil","Canada"]。我想要一个像[["a","Argentina"],["b","Brazil"],["c","Canada"]]这样的列表。 谁能帮帮我吗？感谢。

Answer 1

在没有看到你的用例的情况下我会猜测元组实际上足够了，并且更安全，因此这只是zip

x = ["a","b","c"]
y = ["Argentina","Brazil","Canada"]
z = zip x y

Prelude> z
[("a","Argentina"),("b","Brazil"),("c","Canada")]

Answer 2

我不确定是否有更简单的方法，但您可以使用zip生成元组列表，然后使用map返回列表列表。

Prelude> map (\(a,b) -> [a,b]) $ zip ["a","b","c"] ["Argentina","Brazil","Canada"]
[["a","Argentina"],["b","Brazil"],["c","Canada"]]

修改：Daniel Martin指出zipWith更简单。

Prelude> zipWith (\a b -> [a,b]) ["a","b","c"] ["Argentina","Brazil","Canada"]
[["a","Argentina"],["b","Brazil"],["c","Canada"]]

Answer 3

只需使用

zipWith (\x y -> [x,y])