> For the complete documentation index, see [llms.txt](https://docs.atfinity.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.atfinity.io/rule-language/operators/unknown-operators/union_of_any.md).
# UNION\_OF\_ANY
### Description
`UNION_OF_ANY` is the flexible counterpart of [`UNION`](/rule-language/operators/list-operators/union.md).
It creates a combined set of all the lists you provide. Duplicates in the new list will be removed.
If a value or list is not available:
* `UNION_OF_ANY` simply ignores it and combines what is available.
* `UNION`, before returning a result, will ask users to go back and provide the missing list.
### Examples
```
p is Person
UNION_OF_ANY(
p.countries_lived_in,
p.countries_banned_from
)
```
A person in a case has lived in Germany, Switzerland, and Singapore. Being a fine, law abiding citizen, the person has not been banned from any countries.
The above [expression](/rule-language/expressions.md) will result in the list
\[de, ch, sg]
Because `UNION_OF_ANY` is used, the request for ‘countries banned from’ is ignored, because there are none for this person.
Would you have used `UNION` instead, the system would have alerted you to provide one or more countries the person is banned from before giving you the combined list.\
---
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