Binary map in Haskell

Question

Is there a two-operand equivalent to map built into Haskell with a type signature of:

map2 :: (a -> b -> c) -> [a] -> [b] -> [c]

The following equivalence should hold:

map2 operator as bs === [operator a b | (a, b) <- zip as bs]

Example:

ghci> map2 (*) [2,3] [4,5]
[8,15]

Answer 1

The function zipWith does what you need. There are also zipWith3 .. zipWith7 for cases with more than two lists.