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| Data.FiniteMap | | Portability | portable | | Stability | provisional | | Maintainer | libraries@haskell.org |
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| Contents |
- The FiniteMap type
- Construction
- Lookup operations
- Adding elements
- Deleting elements
- Combination
- Extracting information
- Other operations
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| Description |
| A finite map implementation, derived from the paper:
Efficient sets: a balancing act, S. Adams,
Journal of functional programming 3(4) Oct 1993, pp553-562
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| Synopsis |
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| The FiniteMap type |
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| data FiniteMap key elt |
| A mapping from keys to elts. | | Instances | |
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| Construction |
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| emptyFM :: FiniteMap key elt |
| An empty FiniteMap. |
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| unitFM :: key -> elt -> FiniteMap key elt |
| A FiniteMap containing a single mapping |
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| listToFM :: (Ord key) => [(key, elt)] -> FiniteMap key elt |
| Makes a FiniteMap from a list of (key,value) pairs. In the
case of duplicates, the last is taken |
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| Lookup operations |
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| lookupFM :: (Ord key) => FiniteMap key elt -> key -> Maybe elt |
| Looks up a key in a FiniteMap, returning Just v if the key
was found with value v, or Nothing otherwise. |
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| lookupWithDefaultFM :: (Ord key) => FiniteMap key elt -> elt -> key -> elt |
| Looks up a key in a FiniteMap, returning elt if the specified
key was not found. |
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| elemFM :: (Ord key) => key -> FiniteMap key elt -> Bool |
| Returns True if the specified key has a mapping in this
FiniteMap, or False otherwise. |
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| Adding elements |
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| addToFM :: (Ord key) => FiniteMap key elt -> key -> elt -> FiniteMap key elt |
| Adds an element to a FiniteMap. Any previous mapping with the same
key is overwritten. |
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| addToFM_C :: (Ord key) => (elt -> elt -> elt) -> FiniteMap key elt -> key -> elt -> FiniteMap key elt |
| Adds an element to a FiniteMap. If there is already an element
with the same key, then the specified combination function is used
to calculate the new value. |
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| addListToFM :: (Ord key) => FiniteMap key elt -> [(key, elt)] -> FiniteMap key elt |
| Adds a list of elements to a FiniteMap, in the order given in
the list. Overwrites previous mappings. |
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| addListToFM_C :: (Ord key) => (elt -> elt -> elt) -> FiniteMap key elt -> [(key, elt)] -> FiniteMap key elt |
| A list version of addToFM_C. The elements are added in the
order given in the list. |
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| Deleting elements |
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| delFromFM :: (Ord key) => FiniteMap key elt -> key -> FiniteMap key elt |
| Deletes an element from a FiniteMap. If there is no element with
the specified key, then the original FiniteMap is returned. |
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| delListFromFM :: (Ord key) => FiniteMap key elt -> [key] -> FiniteMap key elt |
| List version of delFromFM. |
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| Combination |
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| plusFM :: (Ord key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt |
| Combine two FiniteMaps. Mappings in the second argument shadow
those in the first. |
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| plusFM_C :: (Ord key) => (elt -> elt -> elt) -> FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt |
| Combine two FiniteMaps. The specified combination function is
used to calculate the new value when there are two elements with
the same key. |
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| Extracting information |
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| fmToList :: FiniteMap key elt -> [(key, elt)] |
| Convert a FiniteMap to a [(key, elt)] sorted by Ord key
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| keysFM :: FiniteMap key elt -> [key] |
Extract the keys from a FiniteMap, in the order of the keys, so keysFM == map fst . fmToList
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| eltsFM :: FiniteMap key elt -> [elt] |
Extract the elements from a FiniteMap, in the order of the keys, so eltsFM == map snd . fmToList
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| sizeFM :: FiniteMap key elt -> Int |
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| isEmptyFM :: FiniteMap key elt -> Bool |
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| Other operations |
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| minusFM :: (Ord key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt |
| (minusFM a1 a2) deletes from a1 any mappings which are bound in a2 |
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| foldFM :: (key -> elt -> a -> a) -> a -> FiniteMap key elt -> a |
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| intersectFM :: (Ord key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt |
| (intersectFM a1 a2) returns a new FiniteMap containing
mappings from a1 for which a2 also has a mapping with the same
key. |
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| intersectFM_C :: (Ord key) => (elt1 -> elt2 -> elt3) -> FiniteMap key elt1 -> FiniteMap key elt2 -> FiniteMap key elt3 |
| Returns the interesction of two mappings, using the specified
combination function to combine values. |
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| mapFM :: (key -> elt1 -> elt2) -> FiniteMap key elt1 -> FiniteMap key elt2 |
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| filterFM :: (Ord key) => (key -> elt -> Bool) -> FiniteMap key elt -> FiniteMap key elt |
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| Produced by Haddock version 0.4 |
