Question

Hi I am using App Engine/Python to do a simple website. I have some trouble with a Django template problem.

In short, I want to use a “ShortName” to access a “LongName”.

The soource code:

LongName={"so":"stackoverflow","su":"superuser"}
ShortName=['so','su']

Then I pass these two parameters to the templates.

In the template I write:

{% for aname in ShortName %}
{{ aname }} stands for {{ LongName.aname }},
{% endfor %}

The output is:

so stands for, su stands for

No error is given. The LongName.aname wont work.

I have no idea whats wrong.

Answer 1

This is trying to access LongName['aname'], not LongName[aname].

You might have to write a custom template tag/filter to get this to work. This Django bug (marked WONTFIX) has a simple implementation:

def get(d, key):
    return d.get(key, '')

register.filter(get)

which you would use by

{{ LongName|get:aname }}

after adding it to your app (that SO answer shows how to do it on GAE).

---

You could also pre-make a variable to loop over in the view, by passing in

 # in view
 name_abbrevs = [(k, LongName[k]) for k in ShortName]

 # in template
 {% for short_name, long_name in name_abbrevs %}
     {{ short_name }} stands for {{ long_name }}
 {% endif %}

---

If you really don’t want to add a template tag — which isn’t that bad! you just make one file! 🙂 — or pass in an extra variable, Vic’s approach will let you do this without touching the Python files at all. As he mentions, it involves a lot of pointless iteration, but it’ll work fine for small lists.