在Haskell中按长度过滤列表项

Question

我有一个清单 ["a","ab","abc", "abcd"]

如何获取仅包含长度> 2的项目的列表.

意味着结果是 ["abc","abcd"].

Answer 1

娜塔莉的回答是完全正确的,但作为一种替代形式,你也可以把它写成

filter ((> 2) . length) ["a", "ab", "abc", "abcd"]

或者列表理解为

[str | str <- ["a", "ab", "abc", "abcd"], length str > 2]

这三个都是等价的

Answer 2

filter (\x -> length x > 2) ["a","ab","abc", "abcd"]