| Portability | portable |
|---|---|
| Stability | provisional |
| Maintainer | libraries@haskell.org |
| Safe Haskell | Safe |
Data.Map
Description
An efficient implementation of ordered maps from keys to values (dictionaries).
This module re-exports the value lazy Lazy API, plus
several value strict functions from Strict.
These modules are intended to be imported qualified, to avoid name clashes with Prelude functions, e.g.
import qualified Data.Map as Map
The implementation of Map is based on size balanced binary trees (or
trees of bounded balance) as described by:
- Stephen Adams, "Efficient sets: a balancing act", Journal of Functional Programming 3(4):553-562, October 1993, http://www.swiss.ai.mit.edu/~adams/BB/.
- J. Nievergelt and E.M. Reingold, "Binary search trees of bounded balance", SIAM journal of computing 2(1), March 1973.
Note that the implementation is left-biased -- the elements of a
first argument are always preferred to the second, for example in
union or insert.
Operation comments contain the operation time complexity in the Big-O notation (http://en.wikipedia.org/wiki/Big_O_notation).
- module Data.Map.Lazy
- insertWith' :: Ord k => (a -> a -> a) -> k -> a -> Map k a -> Map k a
- insertWithKey' :: Ord k => (k -> a -> a -> a) -> k -> a -> Map k a -> Map k a
- insertLookupWithKey' :: Ord k => (k -> a -> a -> a) -> k -> a -> Map k a -> (Maybe a, Map k a)
- fold :: (a -> b -> b) -> b -> Map k a -> b
- foldWithKey :: (k -> a -> b -> b) -> b -> Map k a -> b
Documentation
module Data.Map.Lazy
insertWith' :: Ord k => (a -> a -> a) -> k -> a -> Map k a -> Map k a
Deprecated. As of version 0.5, replaced by insertWith.
O(log n). Same as insertWith, but the combining function is
applied strictly. This is often the most desirable behavior.
For example, to update a counter:
insertWith' (+) k 1 m
insertWithKey' :: Ord k => (k -> a -> a -> a) -> k -> a -> Map k a -> Map k a
Deprecated. As of version 0.5, replaced by insertWithKey.
O(log n). Same as insertWithKey, but the combining function is
applied strictly.
insertLookupWithKey' :: Ord k => (k -> a -> a -> a) -> k -> a -> Map k a -> (Maybe a, Map k a)
Deprecated. As of version 0.5, replaced by
insertLookupWithKey.
O(log n). A strict version of insertLookupWithKey.
foldWithKey :: (k -> a -> b -> b) -> b -> Map k a -> b
Deprecated. As of version 0.4, replaced by foldrWithKey.
O(n). Fold the keys and values in the map using the given right-associative
binary operator. This function is an equivalent of foldrWithKey and is present
for compatibility only.