ansible - example of getting subset of hash using list

easier_output

PLAY [localhost] ***********************************************************************************************************************************************************************************************************************************************************************************************************************************************************

TASK [Gathering Facts] *****************************************************************************************************************************************************************************************************************************************************************************************************************************************************
ok: [localhost]

TASK [set_fact] ************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
ok: [localhost]

TASK [debug] ***************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
ok: [localhost] => {
    "foo": [
        {
            "foo2": "foo2",
            "name": "john"
        },
        {
            "foo3": "foo3",
            "name": "jane"
        }
    ]
}

PLAY RECAP *****************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
localhost                  : ok=3    changed=0    unreachable=0    failed=0

easier_play.yml

---
- hosts: localhost
  gather_facts: True
  connection: local
  vars:
    subset: jane,john
    persons:
      - name: tom
        foo1: foo1
      - name: john
        foo2: foo2
      - name: jane
        foo3: foo3
  tasks:
    - set_fact:
        foo: "{{ persons | selectattr('name', 'in', subset) | list }}"

    - debug:
        var: foo

output

PLAY [localhost] ***********************************************************************************************************************************************************************************************************************************************************************************************************************************************************

TASK [Gathering Facts] *****************************************************************************************************************************************************************************************************************************************************************************************************************************************************
ok: [localhost]

TASK [set_fact] ************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
ok: [localhost] => (item=jane)
ok: [localhost] => (item=john)

TASK [debug] ***************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
ok: [localhost] => {
    "foo": {
        "jane": {
            "foo3": "foo3"
        },
        "john": {
            "foo2": "foo2"
        }
    }
}

PLAY RECAP *****************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
localhost                  : ok=3    changed=0    unreachable=0    failed=0

play.yml

---
- hosts: localhost
  gather_facts: False
  connection: local
  vars:
    subset: jane,john
    persons:
      tom:
        foo1: foo1
      john:
        foo2: foo2
      jane:
        foo3: foo3
  tasks:
    - set_fact:
        foo: "{{ foo | default({}) | combine({item: persons[item]}) }}"
      when: item in subset
      loop: "{{ persons.keys() | list }}"