我在文档中找到的所有相关内容都是 ++ 和 concat。
我一开始认为执行以下操作会给我带来我想要的：
[1, 3, 4] ++ [4, 5, 6]
但如你所知，只给出 [1, 2, 3, 4, 5, 6]。
我需要做什么才能接收 [1, 2, 3] 和 [4, 5, 6] 并输出 [[1, 2, 3], [4, 5, 6]]？
正如评论中提到的，获取两个列表并将它们组合成一个新列表的函数可以定义为：
combine :: [a] -> [a] -> [[a]]
combine xs ys = [xs,ys]
不能多次应用此函数来创建任意数量的列表的列表。这样的函数将采用单个列表和列表列表，并将单个列表添加到列表列表中，因此它的类型为：
push :: [a] -> [[a]] -> [[a]]
这只是(:)， 尽管：
push = (:)
As also mentioned in the comments, the value [x,y] can also be written as x : y : [].1 Since both cases can be done with (:), I would guess that what you really want to use is (:), sometimes consing onto [] and sometimes onto a non-empty list.
1 In fact, [x,y] is just syntactic sugar http://en.wikipedia.org/wiki/Syntactic_sugar for x:y:[].
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