Jinja2 is used for templating.

String manipulation

Substitution

The name is {{ name }}

Upper case

The name is {{ name|upper }}

Title Case

{{ book_name|title }}

Replace

{{ dialogue | replace("Bourne","Bond") }}

Array

Highest number in an array

{{ numbers | max }}

Last number in an array

{{ numbers | last }}

Join

{{ words | join(' ') }}

Number of words

{{ words | wordcount }}

Loops

{% for name_server in name_servers -%}
nameserver {{ name_server }}
{% endfor %}

Input:

{
  "hosts": [
    {
      "name": "web1",
      "ip_address": "192.168.5.4"
    },
    {
      "name": "web2",
      "ip_address": "192.168.5.5"
    },
    {
      "name": "web3",
      "ip_address": "192.168.5.8"
    },
    {
      "name": "db1",
      "ip_address": "192.168.5.9"
    }
  ]
}

{% for host in hosts -%}
{{ host.name }} {{ host.ip_address }}
{% endfor %}

IF

{% for host in hosts -%}
  {% if "web" in host.name %}
{{ host.name }} {{ host.ip_address }}
  {% endif %}
{% endfor %}

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references: Jinja | The Pallets Projects Jinja — Jinja Documentation (3.1.x) (palletsprojects.com)