Issue creating a list of dictionaries in ansible using Jinja2

Question

I am trying to create a list of dictionaries in Ansible by parsing 2 lists and below is the code.

- name: Create list of data dictionary 
  vars:
     _sinfo: |-
       {% for data in data_list|default([]) %}
       {%- if item in data['subject'] %}
       [{ grade: {{data['grade']}}, id: {{data['id']}}, subject: {{data['subject']}} }]
       {%- endif -%}
       {% endfor %}
  set_fact:
    data_dict_list: "{{ data_dict_list|default([]) + _sinfo|list}}"
  with_items: 
    - "{{ subject_list }}"

Above script gives me a list of dictionary with each string broken into letters and using

data_dict_list: "{{ data_dict_list|default([]) + _sinfo|list|join}}"

Gives me error

msg: 'Unexpected templating type error occurred on ({{ data_dict_list|default([]) + _sinfo | list | join}}): can only concatenate list (not "unicode") to list'

List values: [u''Physics'', u''Chemistry'', u''Biology'', u''Math'', u''Geology'']

Inventory file:

data_list:
  - id: 31
    grade: ['A+']
    subject: Physics
  - id: 40
    grade: ['B']
    subject: Math
  - id: 30
    grade: ['A']
    subject: Biology
  - id: 33
    grade: ['A+']
    subject: Physics
  - id: 35
    grade: ['A+', 'B+']
    subject: Physics

Note:
Ansible version: 2.7.7
Python version: 2.7.18
Jinja2 version: 2.11.2

What I am trying to do is to group data by subject and create a list of subjects with each subject dictionary containing all the data with that subject.

_sinfo is not a list it is just a really big string, this is why running list on the string gives you a list of characters. — β.εηοιτ.βε
– β.εηοιτ.βε, Commented Dec 1, 2020 at 20:04
It is just multiline string, see: stackoverflow.com/a/21699210/2123530 — β.εηοιτ.βε
– β.εηοιτ.βε, Commented Dec 1, 2020 at 21:00

Vladimir Botka · Accepted Answer · 2020-12-01 23:48:34Z

1

Q: "Group data by subject and create a list of subjects with each subject dictionary containing all the data with that subject"

A: The tasks below

    - set_fact:
        list_subj: "{{ list_subj|default([]) + [{item.0: item.1}] }}"
      loop: "{{ data_list|groupby('subject') }}"
    - debug:
        var: list_subj

give the list of the dictionaries

  list_subj:
  - Biology:
    - grade:
      - A
      id: 30
      subject: Biology
  - Math:
    - grade:
      - B
      id: 40
      subject: Math
  - Physics:
    - grade:
      - A+
      id: 31
      subject: Physics
    - grade:
      - A+
      id: 33
      subject: Physics
    - grade:
      - A+
      - B+
      id: 35
      subject: Physics

However, a dictionary might be more practical here. For example

    - set_fact:
        dict_subj: "{{ dict(data_list|groupby('subject')) }}"
    - debug:
        var: dict_subj

give

  dict_subj:
    Biology:
    - grade:
      - A
      id: 30
      subject: Biology
    Math:
    - grade:
      - B
      id: 40
      subject: Math
    Physics:
    - grade:
      - A+
      id: 31
      subject: Physics
    - grade:
      - A+
      id: 33
      subject: Physics
    - grade:
      - A+
      - B+
      id: 35
      subject: Physics

edited Dec 1, 2020 at 23:48

answered Dec 1, 2020 at 23:29

Vladimir Botka

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3 Comments

moooni moon Over a year ago

Thanks but i still get the output with strings being broken down to individual characters. What does " [{item.0: item.1}] " do?

Vladimir Botka Over a year ago

What's preventing you from taking a look at - debug: msg: "{{ [{item.0: item.1}] }}" in the loop?

moooni moon Over a year ago

I am new to ansible so was not sure how you can debug within a loop but now i figured that out and thanks for the help. Using dictionary as you suggested worked better.

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