foldl -text

foldl :: (a -> b -> a) -> a -> [b] -> a
base Prelude, base Data.List
foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a list, reduces the list using the binary operator, from left to right: > foldl f z [x1, x2, ..., xn] == (...((z `f` x1) `f` x2) `f`...) `f` xn The list must be finite.
foldl :: Foldable t => (a -> b -> a) -> a -> t b -> a
base Data.Foldable
foldl :: (a -> Char -> a) -> a -> ByteString -> a
bytestring Data.ByteString.Char8, bytestring Data.ByteString.Lazy.Char8
foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a ByteString, reduces the ByteString using the binary operator, from left to right.
foldl :: (a -> Key -> a) -> a -> IntSet -> a
containers Data.IntSet
O(n). Fold the elements in the set using the given left-associative binary operator, such that foldl f z == foldl f z . toAscList. For example, > toDescList set = foldl (flip (:)) [] set
foldl :: (a -> Word8 -> a) -> a -> ByteString -> a
bytestring Data.ByteString.Lazy
foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a ByteString, reduces the ByteString using the binary operator, from left to right.
foldl :: (a -> Word8 -> a) -> a -> ByteString -> a
bytestring Data.ByteString
foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a ByteString, reduces the ByteString using the binary operator, from left to right. This function is subject to array fusion.
foldl :: (a -> b -> a) -> a -> IntMap b -> a
containers Data.IntMap.Strict, containers Data.IntMap.Lazy
O(n). Fold the values in the map using the given left-associative binary operator, such that foldl f z == foldl f z . elems. For example, > elems = reverse . foldl (flip (:)) [] > let f len a = len + (length a) > foldl f 0 (fromList [(5,"a"), (3,"bbb")]) == 4
foldl :: (a -> b -> a) -> a -> Map k b -> a
containers Data.Map.Lazy, containers Data.Map.Strict
O(n). Fold the values in the map using the given left-associative binary operator, such that foldl f z == foldl f z . elems. For example, > elems = reverse . foldl (flip (:)) [] > let f len a = len + (length a) > foldl f 0 (fromList [(5,"a"), (3,"bbb")]) == 4
foldl :: (a -> b -> a) -> a -> Set b -> a
containers Data.Set
O(n). Fold the elements in the set using the given left-associative binary operator, such that foldl f z == foldl f z . toAscList. For example, > toDescList set = foldl (flip (:)) [] set
package foldl
package
This library provides strict left folds that stream in constant memory, and you can combine folds using Applicative style to derive new folds.  Derived folds still traverse the container just once and are often as efficient as hand-written folds. Version 1.0.0
foldl1 :: (a -> a -> a) -> [a] -> a
base Prelude, base Data.List
foldl1 is a variant of foldl that has no starting value argument, and thus must be applied to non-empty lists.
foldl' :: (a -> b -> a) -> a -> [b] -> a
base Data.List
A strict version of foldl.
foldl' :: Foldable t => (a -> b -> a) -> a -> t b -> a
base Data.Foldable
Fold over the elements of a structure, associating to the left, but strictly.
foldl1 :: Foldable t => (a -> a -> a) -> t a -> a
base Data.Foldable
foldl1' :: (a -> a -> a) -> [a] -> a
base Data.List
A strict version of foldl1
foldlM :: (Foldable t, Monad m) => (a -> b -> m a) -> a -> t b -> m a
base Data.Foldable
Monadic fold over the elements of a structure, associating to the left, i.e. from left to right.
foldl' :: (a -> Char -> a) -> a -> ByteString -> a
bytestring Data.ByteString.Char8, bytestring Data.ByteString.Lazy.Char8
'foldl\'' is like foldl, but strict in the accumulator.
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 -> Word8 -> a) -> a -> ByteString -> a
bytestring Data.ByteString.Lazy
'foldl\'' is like foldl, but strict in the accumulator.
foldl' :: (a -> Word8 -> a) -> a -> ByteString -> a
bytestring Data.ByteString
'foldl\'' is like foldl, but strict in the accumulator. However, for ByteStrings, all left folds are strict in the accumulator.

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