DA.TextMap
TextMap - A map is an associative array data type composed of a collection of key/value pairs such that, each possible key appears at most once in the collection.Module Snapshot
Lifecycle
Stable.
Notices
Status:
active
Introduced in: 3.4.9
Removed in: -
Warnings: 0
Deprecations: 0
Deprecated since: -Functions
fromList
fromList : [(Text, a)] -> TextMap a
Create a map from a list of key/value pairs.
fromListWithL
fromListWithL : (a -> a -> a) -> [(Text, a)] -> TextMap a
Create a map from a list of key/value pairs with a combining
function. The combining function is only used when a key appears multiple
times in the list and it takes two arguments: the first one is the new value
being inserted at that key and the second one is the value accumulated so
far at that key.
Examples:
fromListWithR
fromListWithR : (a -> a -> a) -> [(Text, a)] -> TextMap a
Create a map from a list of key/value pairs like fromListWithL
with the combining function flipped. Examples:
fromListWith
fromListWith : (a -> a -> a) -> [(Text, a)] -> TextMap a
toList
toList : TextMap a -> [(Text, a)]
Convert the map to a list of key/value pairs where the keys are
in ascending order.
empty
empty : TextMap a
The empty map.
size
size : TextMap a -> Int
Number of elements in the map.
null
null : TextMap v -> Bool
Is the map empty?
lookup
lookup : Text -> TextMap a -> Optional a
Lookup the value at a key in the map.
member
member : Text -> TextMap v -> Bool
Is the key a member of the map?
filter
filter : (v -> Bool) -> TextMap v -> TextMap v
Filter the TextMap using a predicate: keep only the entries where the
value satisfies the predicate.
filterWithKey
filterWithKey : (Text -> v -> Bool) -> TextMap v -> TextMap v
Filter the TextMap using a predicate: keep only the entries which
satisfy the predicate.
delete
delete : Text -> TextMap a -> TextMap a
Delete a key and its value from the map. When the key is not a
member of the map, the original map is returned.
singleton
singleton : Text -> a -> TextMap a
Create a singleton map.
insert
insert : Text -> a -> TextMap a -> TextMap a
Insert a new key/value pair in the map. If the key is already
present in the map, the associated value is replaced with the
supplied value.
insertWith
insertWith : (v -> v -> v) -> Text -> v -> TextMap v -> TextMap v
Insert a new key/value pair in the map. If the key is already
present in the map, it is combined with the previous value using the given function
f new_value old_value.
union
union : TextMap a -> TextMap a -> TextMap a
The union of two maps, preferring the first map when equal
keys are encountered.
merge
merge : (Text -> a -> Optional c) -> (Text -> b -> Optional c) -> (Text -> a -> b -> Optional c) -> TextMap a -> TextMap b -> TextMap c
Merge two maps. merge f g h x y applies f to all key/value pairs
whose key only appears in x, g to all pairs whose key only appears
in y and h to all pairs whose key appears in both x and y.
In the end, all pairs yielding Some are collected as the result.