Re: [Haskell-cafe] Create a list without duplicates from a list with duplicates

On 8 Feb 2008, news@lyra.net wrote:

Hallo!

Let's suppose I have a list [a,b,c,d,c,d]. I'd like to write a function that returns a new list without duplicates (in the example [a,b,c,d]). How can I do that? What is the most general way? I'd like to use the same function for a list of Int or String or some other user defined data type.

Look at Data.List: nub :: (Eq a) => [a] -> [a] nub = nubBy (==) nubBy :: (a -> a -> Bool) -> [a] -> [a] nubBy eq [] = [] nubBy eq (x:xs) = x : nubBy eq (filter (\ y -> not (eq x y)) xs) Jed