Ansible merge dictionaries using with_items and vars stores only last item - ansible

Question

Trying to create a dictionary per item and merge them
---
- name: TestingLab
hosts: localhost
gather_facts: False
tasks:
- name: Hello Vars
set_fact:
two_nums:
- 1
- 2
- name: create empty dict
set_fact:
ids: {}
- name: Merge all
vars:
single_entry: "{ '{{ item }}': {{ item }} }"
set_fact:
ids: "{{ ids | combine(single_entry) }}"
with_items: "{{ two_nums }}"
- name: Print Result
debug:
msg: "{{ ids }}"
I thought I followed the right guidelines but I seem to be getting only the last item afterwards:
ok: [localhost] => {
"msg": {
"2": 2
} }
I tried replacing the single_entry with the expression in vars but it does not run.
Is there a different syntax to get this done?
EDIT: version info
ansible-playbook 2.5.1
python version = 2.7.17 [GCC 7.5.0]

Answer 1

Try the filters dict and zip. The zip is available since 2.3, e.g.
- set_fact:
d2: "{{ dict(two_nums|zip(two_nums)) }}"
- debug:
var: d2
- debug:
var: d2|type_debug
gives
d2:
1: 1
2: 2
d2|type_debug: dict
If this does not work try Jinja and the filter from_yaml, e.g.
- hosts: localhost
vars:
two_nums:
- 1
- 2
l1: |-
{% for i in two_nums %}
{{ i }}: {{ i }}
{% endfor %}
tasks:
- set_fact:
d1: "{{ l1|from_yaml }}"
- debug:
var: d1
- debug:
var: d1|type_debug
gives the same result
d1:
1: 1
2: 2
d1|type_debug: dict
If you need the keys to be strings quote it, e.g.
l1: |-
{% for i in two_nums %}
"{{ i }}": {{ i }}
{% endfor %}
gives
d1:
'1': 1
'2': 2
In the first case, map the list's items to string, e.g.
- set_fact:
d2: "{{ dict(two_nums|map('string')|zip(two_nums)) }}"
gives the same result
d2:
'1': 1
'2': 2

Answer 2

I can't reproduce the behavior you're describing. Running your
playbook verbatim, I get as output:
TASK [Print Result] **************************************************************************************************************************************************************************
ok: [localhost] => {
"msg": {
"1": 1,
"2": 2
}
}
I'm using Ansible core 2.11.2, but I've also tested your playbook with Ansible 2.9.20 and I get the same output.
I would probably drop the set_fact task, and also change how you're
setting single_entry:
- name: TestingLab
hosts: localhost
gather_facts: False
tasks:
- name: Hello Vars
set_fact:
two_nums:
- 1
- 2
- name: Merge all
vars:
ids: {}
single_entry: "{{ {item: item} }}"
set_fact:
ids: "{{ ids | combine(single_entry) }}"
with_items: "{{ two_nums }}"
- name: Print Result
debug:
msg: "{{ ids }}"
In this version, the template expression is returning a dictionary,
and only requires a single set of Jinja template markers. I'm curious
if this version behaves any differently for you.