Six Django template tags not often used in tutorials

highcenburg
Oct 6 · 3 min read

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 about them.

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

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 widthratio 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 %}

highcenburg

Written by

I’m a Freelance Developer & a Volunteer Developer at Project Website.

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