如何检查django模板中是否存在模型实例

Question

I have a django app with a basic model (Job). Now in my template I would like to check if an instance exists of that model or not. I want to project a text if there is nothing yet to show, otherwise I'd like to show the model attributes.

Somehow like so (which obviously doesn't work):

{% if job.title != "" %}

{{ job.title }}

{% else %}

hola

{% endif %}

Also tried:

 {% for job in jobs %}

      {% if job.title %}
      {{ job.title }}
      {% else %}
      Hola
      {% endif %}

  {% endfor %}

It makes sense it doesn't work because how can I loop through it or return something if it doesn't exist. Is there a simple way to even do that in a template? Or do I have to write my own function? Or what would be a way to do that?

Help is of course very much appreciated

Answer 1

You can use the {% if %} tag. As Django doc says :

The {% if %} tag evaluates a variable, and if that variable is “true” (ie exists, is not empty, and is not a false boolean value) the contents of the block are output.

So you can do something like this:

{% if job %}

{{ job.title }}

{% else %}

<p>Hi from Uruguay</p>

{% endif %}

If you need this inside a for, as @dirkgroten said, you need to use the {% empty %} tag. There is an example in the Django doc.