intersection package:dependent-map

intersection :: GCompare k => DMap k f -> DMap k f -> DMap k f

O(m * log (n/m + 1), m <= n. Intersection of two maps. Return data in the first map for the keys existing in both maps. (intersection m1 m2 == intersectionWith const m1 m2).

intersectionWithKey :: GCompare k => (forall v . k v -> f v -> g v -> h v) -> DMap k f -> DMap k g -> DMap k h

dependent-map Data.Dependent.Map

O(m * log (n/m + 1), m <= n. Intersection with a combining function.