Vicente G. Reyes
Vicente Garcia-Reyes

Vicente Garcia-Reyes

Six Django template tags not often used in tutorials

Vicente G. Reyes's photo
Vicente G. Reyes
·Oct 6, 2019·

6 min read

Subscribe to my newsletter and never miss my upcoming articles

This article is for those who don't read the documentation, and I, who had the Dash app for a few months now, which I never tinkered until last night.

During my first day on my internship a couple of months back, I was tasked to work on the scaffold of the company on which I was overwhelmed with the tags on it and never really bothered to research them.

Some of these are taken from the scaffold, some not.

Side note: There are spaces on the template tag because I have not figured out how to make the tags work on this site.

1.) for...empty

  • The for tag can take an optional {% empty %} clause whose text is displayed if the given array is empty or could not be found:
{% for student in student_list %}
    ...
{% empty %}
    ...
{% endfor %}

Which is also equivalent to:


  {% if student_list %}
    {% for student in student_list %}
      ...
    { % endfor %}
  {% else %}
    ...
  {% endif %}

2.) lorem

  • No, you don't need any other packages nor copy/paste a lorem text. This tag displays random “lorem ipsum” Latin text. This is useful for providing sample data in templates. Unless, of course, you don't.
{%  lorem [count] [method] [random] %}

e.g.

- {% lorem %} # will output the common “lorem ipsum” paragraph.
- {% lorem 3 p %} # will output the common “lorem ipsum” paragraph and two random paragraphs each wrapped in HTML <p> tags.
- {% lorem 2 w random %} # will output two random Latin words.

3.) now

  • Displays the current date and/or time, using a format according to the given string. Such string can contain format specifiers characters as described in the date filter section.
{% now "jS F Y" %}

4.) resetcycle

  • Resets a previous cycle so that it restarts from its first item at its next encounter. Without arguments, {% resetcycle %} will reset the last {% cycle %} defined in the template.
{% for coach in coach_list %}
      {{ coach.name }}
    {% for athlete in coach.athlete_set.all %}
        <p class="{% cycle 'odd' 'even' %}">{{ athlete.name }}</p>
    {% endfor %}
    {% resetcycle %}
{% endfor %}

This example would return this HTML:

<h1>José Mourinho</h1>
<p class="odd">Thibaut Courtois</p>
<p class="even">John Terry</p>
<p class="odd">Eden Hazard</p>

<h1>Carlo Ancelotti</h1>
<p class="odd">Manuel Neuer</p>
<p class="even">Thomas Müller</p>

5.) verbatim

  • Stops the template engine from rendering the contents of this block tag.

  • A common use is to allow a JavaScript template layer that collides with Django’s syntax. For example:

{% verbatim %}
    {{if dying}}Still alive.{{/if}}
{% endverbatim %}
  • You can also designate a specific closing tag, allowing the use of {% endverbatim %} as part of the unrendered contents:
    {% verbatim myblock %}
      Avoid template rendering via the {% verbatim %}{% endverbatim %} block.
    {% endverbatim myblock %}
    

6.) widthratio

  • For creating bar charts and such, this tag calculates the ratio of a given value to a maximum value, and then applies that ratio to a constant.
<img src="#" alt="Imagine an image here"
     height="10" width="{% widthratio this_value max_value max_width %}" />
  • If this_value is 175, max_value is 200, and max_width is 100, the image in the above example will be 88 pixels wide (because 175/200 = .875; .875 * 100 = 87.5 which is rounded up to 88).

  • In some cases, you might want to capture the result of the width ratio in a variable. It can be useful, for instance, in a blocktrans like this:

{% widthratio this_value max_value max_width as width %}
{% blocktrans %}The width is: {{ width }}{% endblocktrans %}

Final side note: There are spaces on the template tag because I have not figured out how to make the tags work on this site.

Buy Me A Coffee

 
Share this

Impressum

Code snippets/words may be mine unless otherwise stated on each article.