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Exact lookup

1. lookup :: Int -> MonoidalIntMap a -> Maybe a

   monoidal-containers	Data.IntMap.Monoidal.Strict

   No documentation available.

2. lookup :: Ord k => k -> MonoidalMap k a -> Maybe a

   monoidal-containers	Data.Map.Monoidal

   No documentation available.

3. lookup :: Ord k => k -> MonoidalMap k a -> Maybe a

   monoidal-containers	Data.Map.Monoidal.Strict

   No documentation available.

4. lookup :: Ord k => k -> MultiMap k a -> [a]

   multimap	Data.MultiMap

   O(log n). Lookup the value at a key in the map. The function will return the corrsponding values as a List, or the empty list if no values are associated witht the given key.

5. lookup :: Ord k => k -> SetMap k a -> Set a

   multimap	Data.SetMap

   O(log n). Lookup the value at a key in the map. The function will return the corrsponding values as a List, or the empty list if no values are associated witht the given key.

6. lookup :: Key -> NEIntMap a -> Maybe a

   nonempty-containers	Data.IntMap.NonEmpty

   O(log n). Lookup the value at a key in the map. The function will return the corresponding value as (Just value), or Nothing if the key isn't in the map. An example of using lookup:

   import Prelude hiding (lookup)
   import Data.Map.NonEmpty
   
   employeeDept = fromList (("John","Sales") :| [("Bob","IT")])
   deptCountry = fromList (("IT","USA") :| [("Sales","France")])
   countryCurrency = fromList (("USA", "Dollar") :| [("France", "Euro")])
   
   employeeCurrency :: String -> Maybe String
   employeeCurrency name = do
   dept <- lookup name employeeDept
   country <- lookup dept deptCountry
   lookup country countryCurrency
   
   main = do
   putStrLn $ "John's currency: " ++ (show (employeeCurrency "John"))
   putStrLn $ "Pete's currency: " ++ (show (employeeCurrency "Pete"))
   

   The output of this program:

   John's currency: Just "Euro"
   Pete's currency: Nothing
   

7. lookup :: Ord k => k -> NEMap k a -> Maybe a

   nonempty-containers	Data.Map.NonEmpty

   O(log n). Lookup the value at a key in the map. The function will return the corresponding value as (Just value), or Nothing if the key isn't in the map. An example of using lookup:

   import Prelude hiding (lookup)
   import Data.Map.NonEmpty
   
   employeeDept = fromList (("John","Sales") :| [("Bob","IT")])
   deptCountry = fromList (("IT","USA") :| [("Sales","France")])
   countryCurrency = fromList (("USA", "Dollar") :| [("France", "Euro")])
   
   employeeCurrency :: String -> Maybe String
   employeeCurrency name = do
   dept <- lookup name employeeDept
   country <- lookup dept deptCountry
   lookup country countryCurrency
   
   main = do
   putStrLn $ "John's currency: " ++ (show (employeeCurrency "John"))
   putStrLn $ "Pete's currency: " ++ (show (employeeCurrency "Pete"))
   

   The output of this program:

   John's currency: Just "Euro"
   Pete's currency: Nothing
   

8. lookup :: Int -> NESeq a -> Maybe a

   nonempty-containers	Data.Sequence.NonEmpty

   The element at the specified position, counting from 0. If the specified position is negative or at least the length of the sequence, lookup returns Nothing. Unlike index, this can be used to retrieve an element without forcing it.

9. lookup :: Eq a => a -> [(a, b)] -> Maybe b

   prelude-compat	Data.List2010

   No documentation available.

10. lookup :: Eq a => a -> [(a, b)] -> Maybe b

    prelude-compat	Prelude2010

    No documentation available.

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