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very simple haskell question

I am just starting Haskell and trying to write an alternative function for returning the last element of a list by using the !! function. I have tried...

mylast xs = xs !! (length [xs] - 1)

but this always returns the head of the list. What am I doing wrong?
TIA,
Chad.

I did say it was very simple...
like the author.

By Chad950 at 2009-07-28 17:04 | LtU Forum | previous forum topic | next forum topic | other blogs | 4227 reads

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Better forums for this type of question

Chad, you may have better luck with questions like this in the future on http://stackoverflow.com/.

In short, the answer to your question is that [xs] is a list with one elements, namely xs. You want ((length xs) - 1), but you have ((length [xs]) - 1) = ((1) - 1) = 0.

By Douglas McClean at Tue, 2009-07-28 17:13 | login or register to post comments

Yep...

... on both counts. I haven't tried Stack Overflow yet, though it's very popular and it looks pretty good. Another alternative is to come to the Haskell IRC channel, which is a wonderful place to get simple questions like this answered, 24/7!

By Leon P Smith at Tue, 2009-07-28 20:16 | login or register to post comments

newsgroups as well

comp.lang.haskell seems friendly enough.

By raould at Mon, 2009-08-03 22:52 | login or register to post comments