rules.
Map type, used for simple key-value mappings.
Keys must be of type rules.String.
In addition to the methods listed below, maps have the following operators:
| Operator | Usage |
|---|---|
x == y |
Compare maps x and y |
x[k] |
Index operator, get value at key name k |
x.k |
Get value at key name k |
k in x |
Check if key k exists in map x |
Methods
diff
diff(map_to_compare) returns rules.MapDiff
Return a rules.MapDiff representing the result of comparing the current Map to a comparison Map.
Parameter |
|
|---|---|
|
map_to_compare |
A Map to which the current (calling) Map will be compared. Value must not be null. |
- Returns
-
non-null rules.MapDiffobject representing the result of the comparison.
get
get(key, default_value) returns value
Returns the value associated with a given search key string.
For nested Maps, involving keys and sub-keys, returns the value associated with a given sub-key string. The sub-key is identified using a list, the first item of which is a top-level key and the last item the sub-key whose value is to be looked up and returned. See the nested Map example below.
The function requires a default value to return if no match to the given search key is found.
Parameter |
|
|---|---|
|
key |
(non-null rules.String or non-null rules.List) Either a key specified as a string, or for nested Maps, a sub-key specified using list syntax. |
|
default_value |
default_value Value to return if the Map does not contain the given search key. Can be any Rules language type. |
- Returns
-
valueValue corresponding to the givenkey, or the default return value specified bydefault_valueif no match to the given key is found. Since Map contents are user-defined, the data type of the returnedvaluecan be any Rules language type.
Example
// "c" is not a key in the supplied Map, returns default value 7.
{"a": 3,"b": 2}.get("c", 7) == 7
// Default result can be any type, e.g. a list such as [1, 1].
{"a": [2, 7], "b": [9, 12]}.get("c", [1, 1]) == [1, 1]
// Return a list on a successful match.
{"a": [2, 7],"b": [9, 12]}.get("b", [1, 1]) == [9, 12]
// For nested Maps, use list ["a", "b"] to specify lookup on sub-key "b".
{"a": {"b": 1},"c": 2}.get(["a", "b"], 7) == 1keys
keys() returns rules.List
Get the list of keys in the map.
- Returns
-
non-null rules.Listlist of keys.
size
size() returns rules.Integer
Get the number of entries in the map.
- Returns
-
non-null rules.Integernumber of entries.
values
values() returns rules.List
Get the list of values in the map.
- Returns
-
non-null rules.Listlist of values.