[Haskell-beginners] function defenition. Do I understand it right?

[Roelof Wobben]

Hello, 

Thanks for the tip.
Im stuck now.

I have this : 

halve (xs) | length xs'mod'2 == 0   = (take n xs drop n xs)
           | otherwise = (take n+1 xs  drop n+1 xs
           where n= lenght xs'div'2 


main = do
  putStrLn $ show $ halve [1,2,3,4]
  putStrLn $ show $ halve [1,2,3]

But now I get this message :

ERROR line 3 - Syntax error in expression (unexpected keyword "where")

Appearently I can't use where here.

How can I solve this ?

Roelof



> Date: Mon, 11 Jul 2011 11:44:28 -0400
> Subject: Re: [Haskell-beginners] function defenition. Do I understand it right?
> From: dmcbride at neondsl.com
> To: rwobben at hotmail.com
> CC: beginners at haskell.org
> 
> For simple snippets like this, you can go to
> http://codepad.org/ddySVOPr and run your code to see if it works.
> 
> And your first version (once corrected for syntax) works on any list
> length except for empty lists.
> 
> On Mon, Jul 11, 2011 at 10:48 AM, Roelof Wobben <rwobben at hotmail.com> wrote:
> > Hello,
> >
> > I have made a exercise where I must split a even list.
> > The answer is :
> >
> > halve xs = (take n xs  drop n xs)
> >      where n = length xs 'div' 2
> >
> > Now I want to change it so i can split even and not even list,.
> > I thought this can be the answer
> >
> > halve xs =
> >          lenght xs 'mod' 2 = 0  : (take n  xs   drop n xs)
> >          otherwise :  (take n+1 xs  drop n+1 xs)
> >          where
> >              n = length xs 'div' 2
> >
> >
> > Can this be working ?
> > I did not check this on GCHI because Im  re - installing my OS.
> >
> > Regards.
> >
> > Roelof
> >
> >
> > _______________________________________________
> > Beginners mailing list
> > Beginners at haskell.org
> > http://www.haskell.org/mailman/listinfo/beginners
> >
> >
 		 	   		  
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