---
- hosts: localhost
  gather_facts: no

  vars:
    demo_list:
      - ip: 1.2.3.4
        id: 1
        name: demo1
      - ip: 2.2.3.4
        id: 2
        name: demo2
      - ip: 3.2.3.4
        id: 3
        name: demo3

    user_list:
      - name: erika
        comment: "bla"
        id: 1001
      - name: max
        id: 1002
        comment: "jo"
        shell: /bin/false

  tasks:
    - name: the list
      debug:
        msg: "{{ user_list }}"
    - name: names
      debug:
        msg: "{{ item.name }} + {{ item.id }} + {{ item.shell | default('/bin/bash') }}"
      loop:
        "{{ user_list }}"



    #    - name: the list
    #  debug:
    #    msg: "{{ demo_list }}"

    #- name: unflattened list
    #  debug:
    #    msg: "{{ item.id }} {{ item.ip }} {{ item.name }}"
          #msg: "{{ item.name }}"
          #  loop:
          #"{{ demo_list }}"

    #- name: flattened list == unflattened list in this case
    #  debug:
    #    msg: "{{ item.id }} {{ item.ip }} {{ item.name }}"
    #  loop:
    #    "{{ demo_list | flatten(levels=1) }}"
...