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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. The already present element is passed as
the first argument and the new element to add as second. |
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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 |
