foldl' +containers

foldl' :: (a -> Key -> a) -> a -> IntSet -> a
containers Data.IntSet
O(n). A strict version of foldl. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldl' :: (a -> b -> a) -> a -> IntMap b -> a
containers Data.IntMap.Strict, containers Data.IntMap.Lazy
O(n). A strict version of foldl. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldl' :: (a -> b -> a) -> a -> Map k b -> a
containers Data.Map.Lazy, containers Data.Map.Strict
O(n). A strict version of foldl. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldl' :: (a -> b -> a) -> a -> Set b -> a
containers Data.Set
O(n). A strict version of foldl. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.