[Haskell-cafe] Re: Ultra-newbie Question

[Henrique Becker]

Thanks, It's my first post.

If you not import Prelude is more clear (N. is horrible):

import Prelude ((-), Integral)
import Data.Number.Nat (drop, length, toNat)

lastN :: Integral b => b -> [a] -> [a]
lastN n xs = drop (length xs - n') xs
        where n' = toNat n

P.S.: You benchmarked? I didn't...

2010/9/20, Luke Palmer <lrpalmer at gmail.com>:
> On Mon, Sep 20, 2010 at 5:11 PM, Luke Palmer <lrpalmer at gmail.com> wrote:
>> On Sun, Sep 19, 2010 at 5:01 PM, Henrique Becker
>> <henriquebecker91 at gmail.com> wrote:
>>> Why not?
>>>
>>> import Data.Number.Nat as N
>>>
>>> lastN :: Integral b => b -> [a] -> [a]
>>> lastN n xs = N.drop (N.length xs - n') xs
>>>        where n' = N.toNat n
>>
>> Wow.  That is gorgeous!  I think it's basically the same idea as my
>> "zipWith" implementation, but it is so much clearer here.  Thanks :-)
>
> Er forget that zipWith comment.  It is quite unlike that. But it is
> still beautiful and efficient.
>