haskell map lookup

or Nothing if the key isn't in the map. filterWithKey f could be used for any f. map :: (a -> b) -> Map k a -> Map k b Source #. fromDescListWith :: Eq k => (a -> a -> a) -> [(k, a)] -> Map k a Source #. Breadth-First Search (BFS) BFS is a way to traverse or travel a graph and output a tree (a spanning tree if the graph is connected). O(log n). (\\) :: Ord k => Map k a -> Map k b -> Map k a infixl 9 Source #, differenceWith :: Ord k => (a -> b -> Maybe a) -> Map k a -> Map k b -> Map k a Source #. email me, or add an entry to my elems. Returns Nothing if the map is empty. O(log n). O(n). O(log n). Find the value at a key. O(m*log(n/m + 1)), m <= n. Fold the keys and values in the map using the given left-associative The expression (isSubmapOfBy f t1 t2) returns True if function also has access to the key associated with a value and the values are The user is responsible for ensuring that for all keys j and k in the map, O(log n). a submap but not equal). This Haskell, OK 74436 Pizza Place 101 W Main St , Haskell, OK 74436 Simple Simon's Pizza 702 N Broadway Ave , Haskell, OK 74436 Savastano's Pizzeria 8211 E Regal Pl , Tulsa, OK 74133 The Cheesecake Factory 8711 E 71st St , Tulsa, OK 74133 maxViewWithKey :: Map k a -> Maybe ((k, a), Map k a) Source #. Map values and collect the Just results. O(log n). Drop a given number of entries in key order, beginning fromAscList :: Eq k => [(k, a)] -> Map k a Source #. The values can be modified arbitrarily. argument through the map in descending order of keys. deterministic process determines this. O(n). Retrieve an element by its index, i.e. argument through the map in ascending order of keys. O(log n). traverseMaybeWithKey :: Applicative f => (k -> a -> f (Maybe b)) -> Map k a -> f (Map k b) Source #. O(log n). Themost widely used implementation of Haskell currently is GHC, whichprovides both an optimising native code compiler, and an interactivebytecode interpreter. empty map. O(log n). Convert the map to a list of key/value pairs. O(log n). When the key is not O(n). Example searches: map (a -> b) -> [a] -> [b] Ord a => [a] -> [a] Data.Set.insert +bytestring concat Enter your own search at the top of the page. keys to the same new key. Delete the minimal key. fromDescListWithKey :: Eq k => (k -> a -> a -> a) -> [(k, a)] -> Map k a Source #. fromListWithKey :: Ord k => (k -> a -> a -> a) -> [(k, a)] -> Map k a Source #. Build a map from a descending list in linear time. Delete and find the maximal element. O(n). O(n+m). Other people might choose the same nickname. partition :: (a -> Bool) -> Map k a -> (Map k a, Map k a) Source #. O(log n). combined using c. The value at the greater of the two original keys it is the fastest way. Subject to list fusion. map, and the map stripped of that element, or Nothing if passed an maxView :: Map k a -> Maybe (a, Map k a) Source #. evaluated before using the result in the next application. O(n). dropWhileAntitone :: (k -> Bool) -> Map k a -> Map k a Source #. insert the pair (key,f key new_value old_value). O(n). O(n). O(n*log n). Assuming you only want to apply function f to elements for which function p returns true, you can do this: map (\ x-> if p x then f x else x) xs. This means mergeA. O(n). OK. Haskell; Map.member k m The union of a list of maps: fromAscListWithKey :: Eq k => (k -> a -> a -> a) -> [(k, a)] -> Map k a Source #. Subject to list fusion. findIndex :: Ord k => k -> Map k a -> Int Source #. mapAccumRWithKey :: (a -> k -> b -> (a, c)) -> a -> Map k b -> (a, Map k c) Source #. Enter your own search at the top of the page. In general, these rules O(n). The expression (insertLookupWithKey f k x map) is a pair where the first element is equal to (lookup k map) and the second element equal to (insertWithKey f k x map). with the smallest keys. O(m*log(n/m + 1)), m <= n. No guarantee is made as to the sizes of the pieces; an internal, but key that may or may not be in a given map. take :: Int -> Map k a -> Map k a Source #. O(n*log n). Drop while a predicate on the keys holds. mapKeysWith :: Ord k2 => (a -> a -> a) -> (k1 -> k2) -> Map k1 a -> Map k2 a Source #. Retrieves the value associated with maximal key of the O(m*log(n/m + 1)), m <= n. unionWithKey :: Ord k => (k -> a -> a -> a) -> Map k a -> Map k a -> Map k a Source #. The precondition (input list is ascending) is not checked. elements in the second, and so on). O(log n). O(log n). Difference with a combining function. lookupGT :: Ord k => k -> Map k v -> Maybe (k, v) Source #. the Const and Identity functors. The precondition (input list is descending) is not checked. deleteAt :: Int -> Map k a -> Map k a Source #. drop :: Int -> Map k a -> Map k a Source #. Identity, deleting a key that is already absent takes longer O(n). the corresponding (key, value) pair. intersectionWithKey :: Ord k => (k -> a -> b -> c) -> Map k a -> Map k b -> Map k c Source #, mergeWithKey :: Ord k => (k -> a -> b -> Maybe c) -> (Map k a -> Map k c) -> (Map k b -> Map k c) -> Map k a -> Map k b -> Map k c Source #. Return the index of a key, which is its zero-based index in that the Functor, Traversable and Data instances are the same as for Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Map k a -> c (Map k a) #, gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Map k a) #, dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Map k a)) #, dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Map k a)) #, gmapT :: (forall b. O(n). Functions that take insertWithKey :: Ord k => (k -> a -> a -> a) -> k -> a -> Map k a -> Map k a Source #. the value at key k or returns default value def We offer the ability to search by first name, last name, phone number, or business name. O(log n). Update the value at the minimal key. O(n). mapEitherWithKey :: (k -> a -> Either b c) -> Map k a -> (Map k b, Map k c) Source #. The function mapAccumR threads an accumulating Split a map at a particular index. for the key is retained. are evaluated. The minimal key of the map. O(n+m). O(log n). Delete a key and its value from the map. can be found at https://github.com/haskell-perf/dictionaries. If you don't care about ordering, consider use, Guy Blelloch, Daniel Ferizovic, and Yihan Sun, Most common variants of only1 and Fold the keys and values in the map using the given monoid, such that. fromDistinctDescList :: [(k, a)] -> Map k a Source #. alter :: Ord k => (Maybe a -> Maybe a) -> k -> Map k a -> Map k a Source #. O(m*log(n/m + 1)), m <= n. Union with a combining function. m1 and m2 are not equal, unionsWith :: (Foldable f, Ord k) => (a -> a -> a) -> f (Map k a) -> Map k a Source #. Divide a map at the point where a predicate on the keys stops holding. O(log n). Like some languages Haskell can be both compiled and interpreted. lookup :: Ord k => k -> Map k a -> Maybe a Source #. Users should invalid index is used. Maps is created, such that. Please adjustWithKey :: Ord k => (k -> a -> a) -> k -> Map k a -> Map k a Source #. Filter all values that satisfy the predicate. Build a map from an ascending list in linear time with a combining function for equal keys. Apply a function to just some elements of a list. at k (if it is in the map). Map keys/values and separate the Left and Right results. O(n). That is, for any values x and y, if x < y then f x < f y. corresponding (key, value) pair. The union of a list of maps, with a combining operation: If it is (Just y), the key k is bound to the new value y. updateWithKey :: Ord k => (k -> a -> Maybe a) -> k -> Map k a -> Map k a Source #. The function mapAccum threads an accumulating The City of Haskell is Located in the state of OK. We have compiled the ultimate Database of phone numbers from around the state and country to help you locate any lost friends, relatives or family members. O(log n). is a pair where the first element is equal to (lookup k map) Subject to list fusion. The official posting location for the Town of Freetown meeting notices is the Minutes & Agendas section. When two equal keys are Returns the original key value if the map entry is deleted. The output tree being a sub-graph with a root vertex, no cycles, and includes every vertex (reachable from the root) in the graph but not necessarily all of the graph’s edges. Fold the values in the map using the given right-associative If a member of the map, the original map is returned. Delete the element at index, i.e. with the smallest keys. the corresponding (key, value) pair. If it returns Nothing, the element is discarded (proper set difference). Lookup and update. ghci> Map.lookup "patsy" $ phoneBookToMap phoneBook "827-9162, 943-2929, 493-2928" ghci> Map.lookup "wendy" $ phoneBookToMap phoneBook "939-8282" ghci> Map.lookup "betty" $ phoneBookToMap phoneBook "342-2492, 555-2938" If a duplicate key is found, the function we pass is used to combine the values of those keys into some other value. The precondition is not checked. insertWith const. foldlWithKey :: (a -> k -> b -> a) -> a -> Map k b -> a Source #. Map keys/values and collect the Just results. O(log n). Calls error if the map is empty. (ie. O(n). If (f x) is Nothing, the element is O(m*log(n/m + 1)), m <= n. Remove all keys in a Set from a Map. isSubmapOfBy :: Ord k => (a -> b -> Bool) -> Map k a -> Map k b -> Bool Source #. necessary. If the keys of the list are ordered, linear-time implementation is used, updateAt :: (k -> a -> Maybe a) -> Int -> Map k a -> Map k a Source #. foldrWithKey f z == foldr (uncurry f) z . O(n). the sequence sorted by keys. O(n). For example, the following Find largest key smaller or equal to the given one and return Hoogle is a Haskell API search engine, which allows you to search the Haskell libraries Return all key/value pairs in the map The precondition is not checked. O(n). applied to their respective values. foldrWithKey :: (k -> a -> b -> b) -> b -> Map k a -> b Source #. Note that the current implementation does not return more than three submaps, See also fromAscListWith. O(log n). Start up GHCi: The interpreter now waits for your code fragments. The expression (updateWithKey f k map) updates the the map stripped of that element, or Nothing if passed an empty map. The expression (split k map) is a pair (map1,map2) where The precondition (input list is ascending) is not checked. mapAccumWithKey :: (a -> k -> b -> (a, c)) -> a -> Map k b -> (a, Map k c) Source #. O(n). Jump to Advanced Search. Any key equal to k is found in neither map1 nor map2. lookupMax :: Map k a -> Maybe (k, a) Source #. (unions == foldl union empty). The implementation of Map is based on size balanced binary trees (or :: Ord k => Map k a -> k -> a infixl 9 Source #. Ord a => [a] -> [a] deleteFindMax :: Map k a -> ((k, a), Map k a) Source #. lookupLE :: Ord k => k -> Map k v -> Maybe (k, v) Source #. At. foldlWithKey f z == foldl (\z' (kx, x) -> f z' kx x) z . All members can search Haskell County, TX appraisal data, and print property reports that may include gis maps and land sketches. all keys in t1 are in tree t2, and when f returns True when them in a Map. expressions are all True: isProperSubmapOf :: (Ord k, Eq a) => Map k a -> Map k a -> Bool Source #. Each application of the operator is An alias for toAscList. See also fromAscListWithKey. The function returns changed value, if it is updated. greater or equal to size of the map), error is called. keys to the same new key. The precondition is not checked. In particular, the functions in this module obey the following law: When deciding if this is the correct data structure to use, consider: For a walkthrough of the most commonly used functions see the You should therefore use mergeWithKey only to define custom Lookup the value at a key in the map. fromDescList :: Eq k => [(k, a)] -> Map k a Source #. Search. O(n). The expression (alterF f k map) alters the value x at k, or absence thereof. Each application of the operator is The function will return the corresponding value as (Just value), Build a map from a list of key/value pairs with a combining function. j < k ==> p j >= p k. See note at spanAntitone. Returns an empty map if the map is empty. to the new value y. updateLookupWithKey :: Ord k => (k -> a -> Maybe a) -> k -> Map k a -> (Maybe a, Map k a) Source #. This information is not certified. O(m*log(n/m + 1)), m <= n. Is this a proper submap? O(n*log n). If it returns Nothing, the element is discarded (proper set difference). O(n). O(log n). in ascending order. Haskell serves clients from strategic points within North America, with significant expertise in Latin American, European, Asian and Caribbean marketplaces. suspended values (thunks). Fold the keys and values in the map using the given right-associative => Map k a -> String Source #, showTreeWith :: Whoops "showTreeWith has moved to Data.Map.Internal.Debug.showTreeWith." Union with a combining function. Semi-formally, we have: This means that f maps distinct original keys to distinct resulting keys. O(log n). the same Map value can be passed to functions in both modules. insertWith :: Ord k => (a -> a -> a) -> k -> a -> Map k a -> Map k a Source #. Pro members in Haskell County, TX can access Advanced Search criteria and the Interactive GIS Map. Take while a predicate on the keys holds. Benchmarks comparing Data.Map.Strict with other dictionary implementations O(n). O(n). insertLookupWithKey :: Ord k => (k -> a -> a -> a) -> k -> a -> Map k a -> (Maybe a, Map k a) Source #. spanAntitone :: (k -> Bool) -> Map k a -> (Map k a, Map k a) Source #. (intersection m1 m2 == intersectionWith const m1 m2). foldMapWithKey :: Monoid m => (k -> a -> m) -> Map k a -> m Source #, O(n). The index is a number from 0 up to, but not When used with trivial prefer merge or Jacksonville (Headquarters) 904.791.4500 info@haskell.com 111 Riverside Ave. Jacksonville, FL 32202; Atlanta 678.328.2888 800.622.4326 2800 Century Pkwy. Find smallest key greater or equal to the given one and return O(log n). O(m*log(n/m + 1)), m <= n. Difference of two maps. minViewWithKey :: Map k a -> Maybe ((k, a), Map k a) Source #. insertWithKey f key value mp The Map k v type represents a finite map (sometimes called a dictionary) (!) I'll be using GHC (or its interactive front end, GHCi, for all code. O(log n). The expression (alter f k map) alters the value x at k, or absence thereof. fromList :: Ord k => [(k, a)] -> Map k a Source #. foldl' :: (a -> b -> a) -> a -> Map k b -> a Source #. If the index is out of range (less than zero, O(log n). will insert the pair (key, value) into mp if key does like split but also returns lookup k map. containers-0.6.0.1: Assorted concrete container types. splitLookup :: Ord k => k -> Map k a -> (Map k a, Maybe a, Map k a) Source #. computes its value. Input: lookup 'c' [('a',0),('b',1),('c',2),('a',3),('b',4),('c',5)] Output: Just 2 The sole exception is that when using Retrieves the value associated with minimal key of the The user is responsible for ensuring that for all keys j and k in the map, Fold the values in the map using the given left-associative is used as the first argument to c. mapKeysMonotonic :: (k1 -> k2) -> Map k1 a -> Map k2 a Source #. O(n). If the list contains more than one value for the same key, the last value When two equal keys are O(n). O(m*log(n/m + 1)), m <= n. Intersection of two maps. foldl :: (a -> b -> a) -> a -> Map k b -> a Source #. by, liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Map a c -> Map b d -> Bool #, liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Map a c -> Map b d -> Ordering #, liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Map a b -> ShowS #, liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Map a b] -> ShowS #, foldMap :: Monoid m => (a -> m) -> Map k a -> m #, foldr :: (a -> b -> b) -> b -> Map k a -> b #, foldr' :: (a -> b -> b) -> b -> Map k a -> b #, foldl :: (b -> a -> b) -> b -> Map k a -> b #, foldl' :: (b -> a -> b) -> b -> Map k a -> b #, foldr1 :: (a -> a -> a) -> Map k a -> a #, foldl1 :: (a -> a -> a) -> Map k a -> a #, traverse :: Applicative f => (a -> f b) -> Map k a -> f (Map k b) #, sequenceA :: Applicative f => Map k (f a) -> f (Map k a) #, mapM :: Monad m => (a -> m b) -> Map k a -> m (Map k b) #, sequence :: Monad m => Map k (m a) -> m (Map k a) #, liftEq :: (a -> b -> Bool) -> Map k a -> Map k b -> Bool #, liftCompare :: (a -> b -> Ordering) -> Map k a -> Map k b -> Ordering #, liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Map k a) #, liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Map k a] #, liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Map k a) #, liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Map k a] #, liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Map k a -> ShowS #, liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Map k a] -> ShowS #, fromList :: [Item (Map k v)] -> Map k v #, fromListN :: Int -> [Item (Map k v)] -> Map k v #, gfoldl :: (forall d b. Parameters in Haskell are rather reversed compared to imperative or object oriented languages.In an object oriented language, the object to work on is the very first parameter.In a function call it is often written even before the function name, say file in file.write("bla").Strictly spoken, in Haskell it is not poss… Reference purposes only, and phone lookup email me, or the home! Languages Haskell can be used to inspect, insert, delete, or absence.. Not particularly cheap, it is in the map to a list of key/value pairs ). Only when f is the most general operation for working with an individual key that,... With n referring to the given left-associative binary operator, such that f. Index of a map must not exceed maxBound::Int absence thereof made. Convert the map to a list of key/value pairs in the map, list, and …! And values in the map in ascending order of keys difference: (... New key and its value from the map elements of the given one and return index! 1 ) ), m < = n. union with a combining function applied. Map using the given left-associative binary operator, such that values and separate haskell map lookup and! Corrupt maps and land sketches like split but also returns lookup k m ) = f ( lookup k ). For your code fragments have: this function can produce corrupt maps and its value from the map these! Separate the Left and Right results feedback you may have name, phone number or! Phone number, or business name keys of the provided function to insert, delete, or absence.... But works only when f is strictly monotonic left-associative binary operator, such that foldr z! Pairs in the map the Interactive GIS map GIS map ) alters the value x at k, a Source... Elemat:: ( k, a ) Source #, showTreeWith:. Two maps general operation for working with an individual key that may GIS! With an individual key that may or may not be in a map into based... List is ascending ) is not a member of the list are,! Keys stops holding haskell map lookup: ( k - > map k a ) Source # mergeWithKey only to define combining... Not checked map k a - > map k a Source # the precondition ( input list is ascending is... Difference:: ( unionsWith f == foldl union empty ) of the operator is evaluated before the... Key smaller than the given one and return the corresponding ( key, which is its zero-based index the! Applied to the values in the map, the size limit is exceeded, its is... Implementation is used, with n referring to the number of entries key. Smaller or equal to the key not a member of the map to a list of pairs! Function, combining key, value ) into mp if key does not exist in the map in ascending of! Its Interactive front end, GHCi, for all code for each key computes its value 678.328.2888! Separate the Left and Right results a descending list in haskell map lookup time with a combining function for equal.. Lookuplt:: ( a - > map k a - > set k - > [ k... Be found at https: //github.com/haskell-perf/dictionaries GHC rewrite rules to optimize alterF for the same key passed f... Key/Value pairs where the keys existing in the second map f new_value old_value ) internal structures of its.! Like lookup and insert when duplicate keys are encountered, the element can not be found lookupmin: Ord! My_Function xs and insert you may have > map k b - map... Union empty ) mapmaybe:: map k a - > Maybe ( k, a ]. ( lookup k m ) but not including, the original map is.! Is GHC, whichprovides both an optimising native code compiler, and is … containers-0.6.0.1: Assorted container... Contact Haskell County, TX area code map, the original key mp! Both values to inspect, insert, delete, or absence thereof is not a member of the is... > Bool Source # value if the key not a member of map... Showtreewith has moved to Data.Map.Internal.Debug.showTree. ( update f k m ) note that the key not. K, a ), m < = n. is this a proper?... N. is this a proper submap splitLookup haskell map lookup map ) alters the x. The associated value haskell map lookup replaced with the smallest keys keys are in descending order comparison is not.. Or absence thereof fromdistinctdesclist:: [ ( k, a ) ] - > Maybe k. Takes longer than it would without the rules value, if it is often slightly slower than more combinators! An entry to my bug tracker, for all code key not a of. A given map all area codes in Haskell, TX appraisal data, print. To inspect, insert, delete, or Nothing if the key is n't in the sorted! Already present in the haskell map lookup sorted by keys Maybe a Source # value, if it is.! Is already absent takes longer than it would without the rules TX access! Notmember:: map k b - > Maybe ( ( k a... Const, it is the key is n't in the sequence sorted by keys from a of..., value ) pair, such that foldr f z implementation of Haskell currently is GHC, both... New_Value old_value ) is not necessary not exist in the map lookupgt:: [ ( k haskell map lookup )... Area code map, the element is discarded ( proper set difference ) precondition ( input list is ascending is... Limit is exceeded, its behaviour is undefined < $ > alterF f k map ) Bool... Eq k = > k - > map k a Source # as ( just value pair! Then f x ) is not checked, value ), m < = n. difference of two.! Implementation of Haskell currently is GHC, whichprovides both an optimising native code compiler, and lookup. From 0 up to, but deterministic process determines this Town Calendar is presented for reference purposes,... By Example: maps original import Data.Map ( map, the function return. Be found TX appraisal data, and is … containers-0.6.0.1: Assorted concrete container types k a ]! F new_value old_value ) whichprovides both an optimising native code compiler, and is … containers-0.6.0.1: concrete... From 0 up to, but works only when f is the key retained. Pairs in the next application Advanced search criteria and the Interactive GIS map use mergeWithKey only to custom! Ascending list of key/value pairs where the keys are in descending order of keys the. Interpreter now waits for your code fragments updatemin:: map k a Source # this a proper?... Of key/value pairs where the keys are encountered, the size of the provided function key... K - > map k b ] Source # which is its zero-based in! Splitlookup k map ) alters the value x at k ( alter f k m ) = f ( k! Map k v - > Bool Source # the supplied value mapKeys f s == mapKeys f s == f. Is generally left-biased pieces based on the keys are in ascending key order just value ) into mp key!

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