Convert nested list of dicts to dict in Ansible - list

Question

I'm trying to convert a list of dictionary in dictionary. My defined 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"
I need to create a new structure in Ansible starting from the previous converting params to dictionaries like the following:
employee:
- name: bruce
age: 22
params:
"k1": "v1bruce"
"k2": "v2bruce"
- name: alan
age: 25
params:
"k1": "v1alan"
"k5": "v5alan"
- name: carl
age: 43
params:
"k1": "v1carl"
"k2": "v2carl"
"k5": "v5carl"
The key point is that I don't know how many elements my starting list is composed.
Is it possible?
Thanks.

Answer 1

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

Answer 2

Warning: ugly solution ahead.
The base to understand is that your params looks like a transformation of a dict via the dict2items filter. So we have to reverse the operation with items2dict. But since it is nested inside your list of hash, it is not so easy. This is what I came up with:
---
- 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