Dict.Refined

A Dict over any keys with a mapping to comparable.

Data structure

type Dict comparable k v

Dictionary over any keys with a function to map keys to comparable.

Build

empty : (k -> comparable) -> Dict comparable k v

Create an empty dictionary by suppling function used for comparing keys.

singleton : (k -> comparable) -> k -> v -> Dict comparable k v

Create a dictionary with one key-value pair.

insert : k -> v -> Dict comparable k v -> Dict comparable k v

Insert a key-value pair into a dict. Replaces value when there is a collision.

update : k -> (Maybe v -> Maybe v) -> Dict comparable k v -> Dict comparable k v

Update the value of a dict for a specific key with a given function.

remove : k -> Dict comparable k v -> Dict comparable k v

Remove a key-value pair from a dict. If the key is not found, no changes are made.

Query

isEmpty : Dict comparable k v -> Bool

Determine if a dict is empty.

`isEmpty empty == True`

member : k -> Dict comparable k v -> Bool

Determine if a whole key is in a dict.

get : k -> Dict comparable k v -> Maybe v

Get the value associated with a key. If the key is not found, return Nothing.

size : Dict comparable k v -> Int

Determine the number of key-value pairs in the dict.

Lists

keys : Dict comparable k v -> List k

Get all of the keys in a dict, sorted from lowest to highest.

values : Dict comparable k v -> List v

Get all of the values in a dict, in the order of their keys.

toList : Dict comparable k v -> List ( k, v )

Convert a dict into an association list of key-value pairs, sorted by keys.

fromList : (k -> comparable) -> List ( k, v ) -> Dict comparable k v

Convert an association list into a dict.

Transform

map : (k -> a -> b) -> Dict comparable k a -> Dict comparable k b

Apply a function to all values in a dict.

foldl : (k -> v -> b -> b) -> b -> Dict comparable k v -> b

Fold over the key-value pairs in a dict from lowest key to highest key.

foldr : (k -> v -> b -> b) -> b -> Dict comparable k v -> b

Fold over the key-value pairs in a dict from highest key to lowest key.

filter : (k -> v -> Bool) -> Dict comparable k v -> Dict comparable k v

Keep only the key-value pairs that pass the given test.

partition :

(k -> v -> Bool)

-> Dict comparable k v

-> ( Dict comparable k v, Dict comparable k v )

Partition a dict according to some test. The first dict contains all key-value pairs which passed the test, and the second contains the pairs that did not.

Combine

union : Dict comparable k v -> Dict comparable k v -> Dict comparable k v

Combine two dicts. If there is a collision, preference is given to the first dict.

intersect : Dict comparable k v -> Dict comparable k v -> Dict comparable k v

Keep a key-value pair when its key appears in the second dict. Preference is given to values in the first dictionary.

diff : Dict comparable k v -> Dict comparable k v -> Dict comparable k v

Keep a key-value pair when its key does not appear in the second dict.

merge :

(k -> a -> result -> result)

-> (k -> a -> b -> result -> result)

-> (k -> b -> result -> result)

-> Dict comparable k a

-> Dict comparable k b

-> result

The most general way of combining two dicts. You provide three accumulators for when a given key appears:

Only in the left dict.
In both dicts.
Only in the right dict.

You then traverse all the keys from lowest to highest, building up whatever you want.

the-sett/elm-refine/1.1.0