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Within LTS Haskell 24.60 (ghc-9.10.3)

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1. toList :: Map k a -> [(k, a)]

   containers	Data.Map.Strict

   Convert the map to a list of key/value pairs. Subject to list fusion.

   toList (fromList [(5,"a"), (3,"b")]) == [(3,"b"), (5,"a")]
   toList empty == []
   

2. fromAscList :: Eq k => [(k, a)] -> Map k a

   containers	Data.Map.Strict.Internal

   Build a map from an ascending list in linear time. The precondition (input list is ascending) is not checked.

   fromAscList [(3,"b"), (5,"a")]          == fromList [(3, "b"), (5, "a")]
   fromAscList [(3,"b"), (5,"a"), (5,"b")] == fromList [(3, "b"), (5, "b")]
   valid (fromAscList [(3,"b"), (5,"a"), (5,"b")]) == True
   valid (fromAscList [(5,"a"), (3,"b"), (5,"b")]) == False
   

3. fromAscListWith :: Eq k => (a -> a -> a) -> [(k, a)] -> Map k a

   containers	Data.Map.Strict.Internal

   Build a map from an ascending list in linear time with a combining function for equal keys. The precondition (input list is ascending) is not checked.

   fromAscListWith (++) [(3,"b"), (5,"a"), (5,"b")] == fromList [(3, "b"), (5, "ba")]
   valid (fromAscListWith (++) [(3,"b"), (5,"a"), (5,"b")]) == True
   valid (fromAscListWith (++) [(5,"a"), (3,"b"), (5,"b")]) == False
   

   Also see the performance note on fromListWith.

4. fromAscListWithKey :: Eq k => (k -> a -> a -> a) -> [(k, a)] -> Map k a

   containers	Data.Map.Strict.Internal

   Build a map from an ascending list in linear time with a combining function for equal keys. The precondition (input list is ascending) is not checked.

   let f k a1 a2 = (show k) ++ ":" ++ a1 ++ a2
   fromAscListWithKey f [(3,"b"), (5,"a"), (5,"b"), (5,"b")] == fromList [(3, "b"), (5, "5:b5:ba")]
   valid (fromAscListWithKey f [(3,"b"), (5,"a"), (5,"b"), (5,"b")]) == True
   valid (fromAscListWithKey f [(5,"a"), (3,"b"), (5,"b"), (5,"b")]) == False
   

   Also see the performance note on fromListWith.

5. fromDescList :: Eq k => [(k, a)] -> Map k a

   containers	Data.Map.Strict.Internal

   Build a map from a descending list in linear time. The precondition (input list is descending) is not checked.

   fromDescList [(5,"a"), (3,"b")]          == fromList [(3, "b"), (5, "a")]
   fromDescList [(5,"a"), (5,"b"), (3,"a")] == fromList [(3, "b"), (5, "b")]
   valid (fromDescList [(5,"a"), (5,"b"), (3,"b")]) == True
   valid (fromDescList [(5,"a"), (3,"b"), (5,"b")]) == False
   

6. fromDescListWith :: Eq k => (a -> a -> a) -> [(k, a)] -> Map k a

   containers	Data.Map.Strict.Internal

   Build a map from a descending list in linear time with a combining function for equal keys. The precondition (input list is descending) is not checked.

   fromDescListWith (++) [(5,"a"), (5,"b"), (3,"b")] == fromList [(3, "b"), (5, "ba")]
   valid (fromDescListWith (++) [(5,"a"), (5,"b"), (3,"b")]) == True
   valid (fromDescListWith (++) [(5,"a"), (3,"b"), (5,"b")]) == False
   

   Also see the performance note on fromListWith.

7. fromDescListWithKey :: Eq k => (k -> a -> a -> a) -> [(k, a)] -> Map k a

   containers	Data.Map.Strict.Internal

   Build a map from a descending list in linear time with a combining function for equal keys. The precondition (input list is descending) is not checked.

   let f k a1 a2 = (show k) ++ ":" ++ a1 ++ a2
   fromDescListWithKey f [(5,"a"), (5,"b"), (5,"b"), (3,"b")] == fromList [(3, "b"), (5, "5:b5:ba")]
   valid (fromDescListWithKey f [(5,"a"), (5,"b"), (5,"b"), (3,"b")]) == True
   valid (fromDescListWithKey f [(5,"a"), (3,"b"), (5,"b"), (5,"b")]) == False
   

   Also see the performance note on fromListWith.

8. fromDistinctAscList :: [(k, a)] -> Map k a

   containers	Data.Map.Strict.Internal

   Build a map from an ascending list of distinct elements in linear time. The precondition is not checked.

   fromDistinctAscList [(3,"b"), (5,"a")] == fromList [(3, "b"), (5, "a")]
   valid (fromDistinctAscList [(3,"b"), (5,"a")])          == True
   valid (fromDistinctAscList [(3,"b"), (5,"a"), (5,"b")]) == False
   

9. fromDistinctDescList :: [(k, a)] -> Map k a

   containers	Data.Map.Strict.Internal

   Build a map from a descending list of distinct elements in linear time. The precondition is not checked.

   fromDistinctDescList [(5,"a"), (3,"b")] == fromList [(3, "b"), (5, "a")]
   valid (fromDistinctDescList [(5,"a"), (3,"b")])          == True
   valid (fromDistinctDescList [(5,"a"), (3,"b"), (3,"a")]) == False
   

10. fromList :: Ord k => [(k, a)] -> Map k a

    containers	Data.Map.Strict.Internal

    Build a map from a list of key/value pairs. See also fromAscList. If the list contains more than one value for the same key, the last value for the key is retained. If the keys of the list are ordered, a linear-time implementation is used.

    fromList [] == empty
    fromList [(5,"a"), (3,"b"), (5, "c")] == fromList [(5,"c"), (3,"b")]
    fromList [(5,"c"), (3,"b"), (5, "a")] == fromList [(5,"a"), (3,"b")]
    

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