[Haskell-beginners] Selecting single result of function application to list

Hugo Ferreira hmf at inescporto.pt
Thu Nov 3 17:07:01 CET 2011


Hello,

Apologies the simpleton question but I would like to
know how it is done in Haskell. I have a list of values,
and I am applying a function to each of these elements.
The result is a Maybe. I would like to return the first
occurrence which is not a Nothing.

I am considering something like:

selectOne f = take 1 . filter (\e -> case e of
                                        Just _ -> True
                                        _ -> False ) . map f

I this how it is done?

TIA,
Hugo F.





More information about the Beginners mailing list