Important Points
The list of items below are importart in understanding details concerning collections.
- ARRAY, SET, and LIST are the only parameters that DIFFERENCE, UNION, and INTERSECTION function may take.
- The DIFFERENCE, UNION, and INTERSECTION functions must take two or more parameters.
- If there is a mix of set and list parameters, all lists are converted to sets, duplicates removed.
Definitions
ARRAY: This is an extension used to convert a flag enum field to a set of values
COUNT: This is an extension used to count the number of items in the result set.
LIST: A list can contain duplicate items. All items within a list must be of the same type.
SET: All item in a set must be unique. All items within the set must be of the same type.
DIFFERENCE: Returns the set that is items that are only in one set within the parameter sets provided.
UNION: Returns the combined set of items of all parameter sets.
INTERSECTION: Returns the set that is items that are in 'every' parameter set provided.
NOTE: In the CRMLS rules. although supportted, LIST is not used.
Collection Functions
| Function | Expression | Result | Comment |
|---|---|---|---|
| ARRAY | ARRAY(Appliances) | SET('FZ,'GD') | Converts flag enum field to an array |
| COUNT | COUNT(ARRAY(Appliances)) | 2 | Counts the items in the array provided |
| LIST | LIST(1, 2, 2, 3) | LIST(1, 2, 2, 3) | Duplicate items are preserved. |
| SET | SET(1, 2, 2, 3) | SET(1, 2, 3) | Duplicate items are removed. |
| DIFFERENCE | DIFFERENCE(LIST(), LIST()) | LIST() | Collection operators require two or more LIST() or SET() arguments. |
| UNION | UNION(LIST(1, 2), SET(3)) | SET(1, 2, 3) | Arguments of type LIST() are converted to SET(). |
| INTERSECTION | INTERSECTION((LIST(1, 2, 3), LIST(2, 3))) | SET(2, 3) | Since the return type of collection operators is SET(), they can be composed. |