在Haskell中获取列表的最后一个元素的最快方法 [英] Fastest way to get the last element of a list in Haskell

问题描述

获取Haskell中列表的最后一个元素的最快方法是什么？在下一次迭代中，我想删除列表的第一个和最后一个元素。什么是最优雅的方式来做到这一点？我试图列表理解，但看起来效率不高！ $ c>和 init 可以很好地完成一次性工作。然而，它们都是 O（n），所以如果您需要经常处理列表的两端，就像您似乎暗示的那样，您可能需要考虑使用 Data.Sequence 代替，它支持 O（1）插入和移除两端的商品。

What is the fastest way to get the last element of a list in Haskell. Also in next iteration, I want to remove first and last element of the list. What is the most elegant way to do it? I am trying list comprehension, but that does not look very efficient!

解决方案

last and init will do the job just fine for a one-off. However they are both O(n), so if you need to manipulate both ends of a list often, as you seem to imply, you might want to consider using Data.Sequence instead, which supports O(1) insertion and removal of items at both ends.

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