警告：前面有难看的解决方案。

要理解的基础是，您的params看起来像是通过dict2items过滤器对字典进行的转换。因此，我们必须使用items2dict来反转操作。但是由于它嵌套在您的哈希列表中，所以它并不是那么容易。这是我想出的：

---
- hosts: localhost
  gather_facts: False

  vars:
    users:
      - name: bruce
        age: 22
        params:
          - key: "k1"
            value: "v1bruce"
          - key: "k2"
            value: "v2bruce"
      - name: alan
        age: 25
        params:
          - key: "k1"
            value: "v1alan"
          - key: "k5"
            value: "v5alan"
      - name: carl
        age: 43
        params:
          - key: "k1"
            value: "v1carl"
          - key: "k2"
            value: "v2carl"
          - key: "k5"
            value: "v5carl"

  tasks:
    - name: Show raw
      debug:
        var: users

    - name: Transform
      set_fact:
        user_transformed: >-
          {%- set result = [] -%}
          {%- for user in users -%}
            {{
              result.append({
                 'name': user.name,'age': user.age,'params': user.params | items2dict
               })
            }}
          {%- endfor -%}
          {{ result | to_json | from_json }}

    - name: Show transformed
      debug:
        var: user_transformed

循环使用items2dict。例如

- set_fact:
    employee: "{{ employee|default([]) +
                  [{'name': item.name,'age': item.age,'params': item.params|items2dict}] }}"
  loop: "{{ users }}"