在Haskell中按照长度过滤列表项

问题描述

我有一个像 [a，ab，abc，abcd]

的列表

如何得到一个只有长度> 2的项目的列表。

意味着结果是 [abc， abcd]。

解决方案

Natalie的回答完全正确，但作为替代形式，您可以还将其写为

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

或者将列表理解为

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

所有这三个元素都是相同的

I have a list like ["a","ab","abc", "abcd"]

How to get a list that only has the items which have a length > 2.

Means the result is ["abc","abcd"].

解决方案

Natalie's answer is perfectly correct, but as an alternate form you could also write it as

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

Or with list comprehension as

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

All three are equivalent

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