# Alternative f => [f a] -> f a -quickcheck -base -network

The union of a list of maps. > unions [(fromList [(5, "a"), (3, "b")]), (fromList [(5, "A"), (7, "C")]), (fromList [(5, "A3"), (3, "B3")])] > == fromList [(3, "b"), (5, "a"), (7, "C")] > unions [(fromList [(5, "A3"), (3, "B3")]), (fromList [(5, "A"), (7, "C")]), (fromList [(5, "a"), (3, "b")])] > == fromList [(3, "B3"), (5, "A3"), (7, "C")]
The union of a list of maps, with a combining operation. > unionsWith (++) [(fromList [(5, "a"), (3, "b")]), (fromList [(5, "A"), (7, "C")]), (fromList [(5, "A3"), (3, "B3")])] > == fromList [(3, "bB3"), (5, "aAA3"), (7, "C")]
The union of a list of sets: (unions == foldl union empty).
Push the current matrix stack down by one, duplicating the current matrix, excute the given action, and pop the current matrix stack, replacing the current matrix with the one below it on the stack (i.e. restoring it to its previous state). The returned value is that of the given action. Note that a round-trip to the server is probably required. For a more efficient version, see unsafePreservingMatrix.
A more efficient, but potentially dangerous version of preservingMatrix: The given action is not allowed to throw an exception or change the current matrix mode permanently.
O(min(n,W)). Delete the maximal key. Returns an empty map if the map is empty. Note that this is a change of behaviour for consistency with Map  versions prior to 0.5 threw an error if the IntMap was already empty.
O(min(n,W)). Delete the minimal key. Returns an empty map if the map is empty. Note that this is a change of behaviour for consistency with Map  versions prior to 0.5 threw an error if the IntMap was already empty.
O(n). The reverse of a sequence.
O(log n). Delete the maximal element. Returns an empty set if the set is empty.
O(log n). Delete the minimal element. Returns an empty set if the set is empty.