I am trying to make a function in haskell, where a list enters it by parameter and returns or shows the list but that the duplicates are eliminated, that is to say:
Enter [1,2,3,4,1,2] and show [1,2,3,4] . It can also be with characters not necessarily with numbers.
Something like this:
deleteDuplicate :: [a] -> [a]
Haskell's Data.List module already has a function, nub , which removes repeated items from a list in% O(n^2) .
A simple way to define this function is to take the head x of the list (x:xs) , eliminate the occurrences of x in the queue xs (filtering the different elements of x using the function filter ) and recursively remove the repeated elements.
deleteDuplicate :: (Eq a) => [a] -> [a]
deleteDuplicate [] = []
deleteDuplicate (x:xs) = x : deleteDuplicate (filter (/= x) xs)