[Haskell-cafe] Is there a nicer way to do this?

[Evan Laforge]

On Sun, Jul 6, 2008 at 5:25 PM, John Hamilton <jlhamilton at gmail.com> wrote:
> On Sun, Jul 6, 2008 at 16:45, Michael Feathers <mfeathers at mindspring.com> wrote:
>>
>>
>> segment :: Int -> [a] -> [[a]]
>> segment 0 _ = []
>> segment _ [] = []
>> segment n x = (take n x) : segment n (drop n x)
>>
>>
>> I did a version of this which used splitAt but I wasn't sure whether it was
>> going to buy me anything re performance that would justify its ugliness.
>
> You can use
>
>  segment n = takeWhile (not . null) . unfoldr (Just . splitAt n)
>
> I don't know how it compares in performance.  It's from
> http://www.haskell.org/haskellwiki/Blow_your_mind

Watch out for negative numbers, though.