foldr -bytestring -base

foldr :: (Char -> a -> a) -> a -> Text -> a
text Data.Text, text Data.Text.Lazy
O(n) foldr, applied to a binary operator, a starting value (typically the right-identity of the operator), and a Text, reduces the Text using the binary operator, from right to left. Subject to fusion.
foldr :: (Key -> b -> b) -> b -> IntSet -> b
containers Data.IntSet
O(n). Fold the elements in the set using the given right-associative binary operator, such that foldr f z == foldr f z . toAscList. For example, > toAscList set = foldr (:) [] set
foldr :: (a -> b -> b) -> b -> IntMap a -> b
containers Data.IntMap.Strict, containers Data.IntMap.Lazy
O(n). Fold the values in the map using the given right-associative binary operator, such that foldr f z == foldr f z . elems. For example, > elems map = foldr (:) [] map > let f a len = len + (length a) > foldr f 0 (fromList [(5,"a"), (3,"bbb")]) == 4
foldr :: (a -> b -> b) -> b -> Map k a -> b
containers Data.Map.Lazy, containers Data.Map.Strict
O(n). Fold the values in the map using the given right-associative binary operator, such that foldr f z == foldr f z . elems. For example, > elems map = foldr (:) [] map > let f a len = len + (length a) > foldr f 0 (fromList [(5,"a"), (3,"bbb")]) == 4
foldr :: (a -> b -> b) -> b -> Set a -> b
containers Data.Set
O(n). Fold the elements in the set using the given right-associative binary operator, such that foldr f z == foldr f z . toAscList. For example, > toAscList set = foldr (:) [] set
foldr' :: (Key -> b -> b) -> b -> IntSet -> b
containers Data.IntSet
O(n). A strict version of foldr. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldr' :: (a -> b -> b) -> b -> IntMap a -> b
containers Data.IntMap.Strict, containers Data.IntMap.Lazy
O(n). A strict version of foldr. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldr' :: (a -> b -> b) -> b -> Map k a -> b
containers Data.Map.Lazy, containers Data.Map.Strict
O(n). A strict version of foldr. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldr' :: (a -> b -> b) -> b -> Set a -> b
containers Data.Set
O(n). A strict version of foldr. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldr1 :: (Char -> Char -> Char) -> Text -> Char
text Data.Text, text Data.Text.Lazy
O(n) A variant of foldr that has no starting value argument, and thus must be applied to a non-empty Text. Subject to fusion.
foldrChunks :: (Text -> a -> a) -> a -> Text -> a
text Data.Text.Lazy.Internal, text Data.Text.Lazy
Consume the chunks of a lazy Text with a natural right fold.
foldrWithIndex :: (Int -> a -> b -> b) -> b -> Seq a -> b
containers Data.Sequence
foldrWithIndex is a version of foldr that also provides access to the index of each element.
foldrWithKey :: (Key -> a -> b -> b) -> b -> IntMap a -> b
containers Data.IntMap.Strict, containers Data.IntMap.Lazy
O(n). Fold the keys and values in the map using the given right-associative binary operator, such that foldrWithKey f z == foldr (uncurry f) z . toAscList. For example, > keys map = foldrWithKey (\k x ks -> k:ks) [] map > let f k a result = result ++ "(" ++ (show k) ++ ":" ++ a ++ ")" > foldrWithKey f "Map: " (fromList [(5,"a"), (3,"b")]) == "Map: (5:a)(3:b)"
foldrWithKey :: (k -> a -> b -> b) -> b -> Map k a -> b
containers Data.Map.Lazy, containers Data.Map.Strict
O(n). Fold the keys and values in the map using the given right-associative binary operator, such that foldrWithKey f z == foldr (uncurry f) z . toAscList. For example, > keys map = foldrWithKey (\k x ks -> k:ks) [] map > let f k a result = result ++ "(" ++ (show k) ++ ":" ++ a ++ ")" > foldrWithKey f "Map: " (fromList [(5,"a"), (3,"b")]) == "Map: (5:a)(3:b)"
foldrWithKey' :: (Key -> a -> b -> b) -> b -> IntMap a -> b
containers Data.IntMap.Strict, containers Data.IntMap.Lazy
O(n). A strict version of foldrWithKey. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldrWithKey' :: (k -> a -> b -> b) -> b -> Map k a -> b
containers Data.Map.Lazy, containers Data.Map.Strict
O(n). A strict version of foldrWithKey. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
unfoldr :: (a -> Maybe (Char, a)) -> a -> Text
text Data.Text.Lazy
O(n), unfoldr function is analogous to the List unfoldr. unfoldr builds a Text from a seed value. The function takes the element and returns Nothing if it is done producing the Text, otherwise Just (a,b). In this case, a is the next Char in the string, and b is the seed value for further production. Performs replacement on invalid scalar values.
unfoldr :: (a -> Maybe (Char, a)) -> a -> Text
text Data.Text
O(n), unfoldr function is analogous to the List unfoldr. unfoldr builds a Text from a seed value. The function takes the element and returns Nothing if it is done producing the Text, otherwise Just (a,b). In this case, a is the next Char in the string, and b is the seed value for further production. Subject to fusion. Performs replacement on invalid scalar values.
unfoldr :: (b -> Maybe (a, b)) -> b -> Seq a
containers Data.Sequence
Builds a sequence from a seed value. Takes time linear in the number of generated elements. WARNING: If the number of generated elements is infinite, this method will not terminate.
unfoldrN :: Int -> (a -> Maybe (Char, a)) -> a -> Text
text Data.Text
O(n) Like unfoldr, unfoldrN builds a Text from a seed value. However, the length of the result should be limited by the first argument to unfoldrN. This function is more efficient than unfoldr when the maximum length of the result is known and correct, otherwise its performance is similar to unfoldr. Subject to fusion. Performs replacement on invalid scalar values.

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