Fastest way to get the last element of a list in Haskell

Question

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!

Answer 1

You can use the last function to get the last element of a list.

As for how to remove the first and last elements, you could use (init . tail), but I don't know how efficient that is.

I think this image from Learn You A Haskell shows the list functions fairly well:

Answer 2

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.