Some useful filters in DTL are:
- lower
- escape
- linebreaks
- truncatewords
- join
- default
- length
- filesizeformat

List of DTL Filters

https://docs.djangoproject.com/en/3.1/ref/templates/builtins/#ref-templates-builtins-filters

DTL Built-In Filter Reference

You may use external, custom tag and filter libraries in DTL. To access them, first add them to your application's INSTALLED_APPS and then use the following syntax.
```python
{% load library_name %}
```
You may add multiple libraries like so:
```python
{% load library1 library2 library3 %}
```

Custom Tag and Filter Libraries in DTL

Filters may be used in DTL to manipulate variables for display. These are accessed by using a pipe ( | ). For example, to display a variable called "country" in all lowercase, you could do the following:
```python
{{ country|lower }}
```
Filters can be chained together, like so:
```python
{{ summary|truncatewords:15|lower }}
```

University of Michigan - Ann Arbor

Django template language (DTL) is Django's built-in template backend. DTL is used to create text-based templates, meaning that it may be used for any text-based format beyond HTML and XML. It stresses presentation over program logic.

Django Template Language

Django Documentation

In DTL, variables are can be inserted directly into files. They are inserted with curly braces, for example:
```python
{{ variable_name }} #variable
{{ variable_name.attribute }} #attribute of a variable
```
The regular variable naming conventions of Python apply in DTL.

Variables in DTL

Filters in DTL

In DTL, tags are used to perform a variety of actions, including loops, logic, loading external information, and text output. Some tags have both a beginning and end tag, while others just have a single tag. They are formatted as follows:
```python
{% tag %}

{% begin_tag %}
...
{% end_tag %}
```

Tags in DTL

Comments can be added in DTL just as they would in any programming language. The syntax for comments is as follows:
```python
{# Comment Text #}
```
Any content between the {# #} will be commented out.

Comments in DTL

Templates written with DTL can inherit from other templates. To do so, 'blocks' are defined in the parent template that can be replaced by content in child templates. This allows the basic structure of a site to be easily reused across all pages.

Learn Before

Related

Learn After