[Haskell-cafe] defining last using foldr

Chaddaï Fouché chaddai.fouche at gmail.com
Tue Aug 14 17:16:01 EDT 2007

2007/8/14, Alexteslin <alexteslin at yahoo.co.uk>:
> Well, i have tried cons (:) operator but when it passed to foldr doesn't work
> because cons operator operates first character and then the list but the
> foldr argument takes a function (a->a->a).  Maybe i am missing the point
> here?

What Aaron was saying was that in this list :
1 : 2 : 3 : 4 : []
A fold replaced the cons (:) by another function (and [] by another constant).

Your problem isn't so easy to do with a foldr, a foldl would be easier
and a foldr1 or foldl1 even better. Are you sure you can't use one of
those other folds ?


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