Data.IntMap

An efficient implementation of maps from integer keys to values (dictionaries).

This module re-exports the value lazy Data.IntMap.Lazy API, plus several deprecated value strict functions. Please note that these functions have different strictness properties than those in Data.IntMap.Strict: they only evaluate the result of the combining function. For example, the default value to insertWith' is only evaluated if the combining function is called and uses it.

These modules are intended to be imported qualified, to avoid name clashes with Prelude functions, e.g.

  import Data.IntMap (IntMap)
  import qualified Data.IntMap as IntMap

The implementation is based on big-endian patricia trees. This data structure performs especially well on binary operations like union and intersection. However, my benchmarks show that it is also (much) faster on insertions and deletions when compared to a generic size-balanced map implementation (see Data.Map).

• Chris Okasaki and Andy Gill, "Fast Mergeable Integer Maps", Workshop on ML, September 1998, pages 77-86, http://citeseer.ist.psu.edu/okasaki98fast.html
• D.R. Morrison, "/PATRICIA -- Practical Algorithm To Retrieve Information Coded In Alphanumeric/", Journal of the ACM, 15(4), October 1968, pages 514-534.

Operation comments contain the operation time complexity in the Big-O notation http://en.wikipedia.org/wiki/Big_O_notation. Many operations have a worst-case complexity of O(min(n,W)). This means that the operation can become linear in the number of elements with a maximum of W -- the number of bits in an Int (32 or 64).

Documentation

module Data.IntMap.Lazy

insertWith' :: (a -> a -> a) -> Key -> a -> IntMap a -> IntMap a

Deprecated. As of version 0.5, replaced by insertWith.

O(log n). Same as insertWith, but the result of the combining function is evaluated to WHNF before inserted to the map. In contrast to insertWith, the value argument is not evaluted when not needed by the combining function.

insertWithKey' :: (Key -> a -> a -> a) -> Key -> a -> IntMap a -> IntMap a

Deprecated. As of version 0.5, replaced by insertWithKey.

O(log n). Same as insertWithKey, but the result of the combining function is evaluated to WHNF before inserted to the map. In contrast to insertWithKey, the value argument is not evaluted when not needed by the combining function.

fold :: (a -> b -> b) -> b -> IntMap a -> b

Deprecated. As of version 0.5, replaced by foldr.

O(n). Fold the values in the map using the given right-associative binary operator. This function is an equivalent of foldr and is present for compatibility only.

foldWithKey :: (Key -> a -> b -> b) -> b -> IntMap a -> b

Deprecated. As of version 0.5, 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.