ansible.builtin.union filter – union of lists


This filter plugin is part of ansible-core and included in all Ansible installations. In most cases, you can use the short plugin name union. However, we recommend you use the Fully Qualified Collection Name (FQCN) ansible.builtin.union for easy linking to the plugin documentation and to avoid conflicting with other collections that may have the same filter plugin name.


  • Provide a unique list of all the elements of two lists.

  • Items in the resulting list are returned in arbitrary order.


This describes the input of the filter, the value before | ansible.builtin.union.




list / elements=string / required

A list.

Keyword parameters

This describes keyword parameters of the filter. These are the values key1=value1, key2=value2 and so on in the following example: input | ansible.builtin.union(key1=value1, key2=value2, ...)




list / elements=string / required

A list.

See Also

See also

ansible.builtin.difference filter plugin

the difference of one list from another.

ansible.builtin.intersect filter plugin

intersection of lists.

ansible.builtin.symmetric_difference filter plugin

different items from two lists.

ansible.builtin.unique filter plugin

set of unique items of a list.


# return the unique elements of list1 added to list2
# list1: [1, 2, 5, 1, 3, 4, 10]
# list2: [1, 2, 3, 4, 5, 11, 99]
{{ list1 | union(list2) }}
# => [1, 2, 5, 3, 4, 10, 11, 99]

Return Value



Return value

list / elements=string

A unique list of all the elements from both lists.

Returned: success


  • Brian Coca (@bcoca)


Configuration entries for each entry type have a low to high priority order. For example, a variable that is lower in the list will override a variable that is higher up.