community.general.lists_mergeby filter – Merge two or more lists of dictionaries by a given attribute

Note

This filter plugin is part of the community.general collection (version 8.4.0).

You might already have this collection installed if you are using the ansible package. It is not included in ansible-core. To check whether it is installed, run ansible-galaxy collection list.

To install it, use: ansible-galaxy collection install community.general.

To use it in a playbook, specify: community.general.lists_mergeby.

New in community.general 2.0.0

Synopsis

  • Merge two or more lists by attribute index. Optional parameters recursive and list_merge control the merging of the lists in values. The function merge_hash from ansible.utils.vars is used. To learn details on how to use the parameters recursive and list_merge see Ansible User’s Guide chapter “Using filters to manipulate data” section “Combining hashes/dictionaries”.

Input

This describes the input of the filter, the value before | community.general.lists_mergeby.

Parameter

Comments

Input

list / elements=dictionary / required

A list of dictionaries.

Positional parameters

This describes positional parameters of the filter. These are the values positional1, positional2 and so on in the following example: input | community.general.lists_mergeby(positional1, positional2, ...)

Parameter

Comments

another_list

list / elements=dictionary

Another list of dictionaries. This parameter can be specified multiple times.

index

string / required

The dictionary key that must be present in every dictionary in every list that is used to merge the lists.

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 | community.general.lists_mergeby(key1=value1, key2=value2, ...)

Parameter

Comments

list_merge

string

Modifies the behaviour when the dictionaries (hashes) to merge contain arrays/lists.

Choices:

  • "replace" ← (default)

  • "keep"

  • "append"

  • "prepend"

  • "append_rp"

  • "prepend_rp"

recursive

boolean

Should the combine recursively merge nested dictionaries (hashes).

Note: It does not depend on the value of the hash_behaviour setting in ansible.cfg.

Choices:

  • false ← (default)

  • true

Notes

Note

  • When keyword and positional parameters are used together, positional parameters must be listed before keyword parameters: input | community.general.lists_mergeby(positional1, positional2, key1=value1, key2=value2)

Examples

- name: Merge two lists
  ansible.builtin.debug:
    msg: >-
      {{ list1 | community.general.lists_mergeby(
                    list2,
                    'index',
                    recursive=True,
                    list_merge='append'
                 ) }}"
  vars:
    list1:
      - index: a
        value: 123
      - index: b
        value: 42
    list2:
      - index: a
        foo: bar
      - index: c
        foo: baz
  # Produces the following list of dictionaries:
  #   {
  #     "index": "a",
  #     "foo": "bar",
  #     "value": 123
  #   },
  #   {
  #     "index": "b",
  #     "value": 42
  #   },
  #   {
  #     "index": "c",
  #     "foo": "baz"
  #   }

Return Value

Key

Description

Return value

list / elements=dictionary

The merged list.

Returned: success

Authors

  • Vladimir Botka (@vbotka)

Hint

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.