Hi, you don't proof for empty lists, only for empty tails: (x:[]) On 08/31/2012 02:01 PM, Ezequiel Hernan Di Giorgi wrote:
First i want to thank all the persons who responded me yesterday to help me. Thanks! I am so happy with with your friendliness. So i have other beginners question:
Now i want a improved version of my* intercalate*. Now i want to call a function with two [t][t] and obtain another one which have only even elements, even because:
- [1,2,3,3,4][6] and the ouput [1,6] - [1,2,3,4][5,6,7] output [1,5,2,6,3,7]
I tried it:
*intercalate :: (Eq t) => [t] -> [t] -> [t]* *intercalate (x:xs) (y:ys)* * | xt == [] = []* * | yt == [] = []* * | otherwise = x : y : intercalate xs ys* * where xt=(x:xs)* * yt=(y:ys)*
but i get nice error
**Main> intercalate [1][6]* *[1,6*** Exception: baby.hs:(2,1)-(5,51): Non-exhaustive patterns in function intercalate* * * **Main> *
(yes...the file's name is baby.hs)
Thanks in advance! (: (: (: (: (:
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