| Copyright | (c) Daan Leijen 2002 (c) Andriy Palamarchuk 2008 |
|---|---|
| License | BSD-style |
| Maintainer | libraries@haskell.org |
| Stability | provisional |
| Portability | portable |
| Safe Haskell | Safe |
| Language | Haskell98 |
Data.Map
Description
Note: You should use Data.Map.Strict instead of this module if:
- You will eventually need all the values stored.
- The stored values don't represent large virtual data structures to be lazily computed.
An efficient implementation of ordered maps from keys to values (dictionaries).
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.
Bounds for union, intersection, and difference are as given
by
- Guy Blelloch, Daniel Ferizovic, and Yihan Sun, "Just Join for Parallel Ordered Sets", https://arxiv.org/abs/1602.02120v3.
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.
Warning: The size of the map must not exceed maxBound::Int. Violation of
this condition is not detected and if the size limit is exceeded, its
behaviour is undefined.
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 value being inserted to the map is
evaluated to WHNF beforehand.
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 value being inserted to the map is
evaluated to WHNF beforehand.
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). Same as insertLookupWithKey, but the value being inserted to
the map is evaluated to WHNF beforehand.
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.