Zip with default value instead of dropping values?

Question

I\'m looking for a function in haskell to zip two lists that may vary in length.
All zip functions I could find just drop all values of a lists that is longer than the o

Answer 1

You don't have to compare list lengths. Try to think about your zip function as a function taking only one argument xs and returning a function which will take ys and perform the required zip. Then, try to write a recursive function which recurses on xs only, as follows.

type Result = [Int] -> [(Int,Int)]
myZip :: [Int] -> Result
myZip []     = map (\y -> (0,y)) -- :: Result
myZip (x:xs) = f x (myZip xs)    -- :: Result
   where f x k = ???             -- :: Result

Once you have found f, notice that you can turn the recursion above into a fold!