Interface: Map
rules.
Map type, used for simple key-value mappings.
Keys must be of typerules.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 arules.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-nullrules.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 andsub-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-nullrules.String or non-nullrules.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-nullrules.Listlist of keys.
size
size() returns rules.Integer
Get the number of entries in the map.
- Returns
non-nullrules.Integernumber of entries.
values
values() returns rules.List
Get the list of values in the map.
- Returns
non-nullrules.Listlist of values.
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Last updated 2020-03-04 UTC.