How to reference previous instance when looping in a template?

[Richard Brockie]

Hi,

I'm doing a lot of this type of looping in my templates (from the docs: https://docs.djangoproject.com/en/1.9/ref/templates/builtins/#for):

<ul>
{% for athlete in athlete_list %}
    <li>{{ athlete.name }}</li>
{% endfor %}
</ul>

In this context, I find myself occasionally wanting to refer to data of the previous athlete (if the instance exists) while working on the current athlete.

The way I do this right now is within a custom template tag. I copy the data of interest into a session variable for use next time the custom template tag is called. This works, but I'm wondering if there is a better way?

My thought was the following: what if there existed a .previous property attached to the current instance that contains the previous instance for this purpose?

IE:

<ul>
{% for athlete in athlete_list %}
    <li>This time: {{ athlete.name }}, last time: {{ athlete.previous.name }}</li>
{% endfor %}
</ul>

athlete.previous would obviously be None the first time round the loop.