difference package:dependent-map

difference :: GCompare k => DMap k f -> DMap k g -> DMap k f
dependent-map Data.Dependent.Map
O(m * log (n/m + 1)), m <= n. Difference of two maps. Return elements of the first map not existing in the second map.
differenceWithKey :: GCompare k => (forall v . k v -> f v -> g v -> Maybe (f v)) -> DMap k f -> DMap k g -> DMap k f
dependent-map Data.Dependent.Map
O(n+m). Difference with a combining function. When two equal keys are encountered, the combining function is applied to the key and both values. If it returns Nothing, the element is discarded (proper set difference). If it returns (Just y), the element is updated with a new value y.