In Django's template engine, is it possible to run a filter through an entire array?

For example, if I have an array of开发者_开发百科 datetime.date objects, I would like to apply a date format filter to each of its elements, while still making use of the default string representation of the array.

Given a date array that looks like:

[datetime.date(2011, 2, 28), datetime.date(2011, 3, 1), datetime.date(2011, 3, 2)]

Assuming that I already passed it to the template's context, I'd like to do this in the template:

<script>
    // ...
    var dates = {{ my_date_array|date:'b d, Y' }};
    // ...
</script>

so it produces:

    var dates = ['Feb 28, 2011', 'Mar 1, 2011', 'Mar 2, 2011'];

..instead of having to loop through the elements of the array.

Is this possible by default, without creating a custom filter?

Looking at the source, I'd say that's not possible using the default date filter.

You will have to either use a loop in your template, or create a custom filter that accepts a list of date objects.

Update:

It should be relatively easy to create your own filter by making use of the existing one. For example:

from django.template.defaultfilters import date
from django import template
register = template.Library()

# Only mildly tested. Use with caution.
def datelist(values, arg=None):
    try:
        outstr = "', '".join([date(v, arg) for v in values])
    except TypeError: # non-iterable?
        outstr = date(values, arg)
    return "['%s']" % outstr
register.filter('datelist', datelist)

If you don't like that approach for determining iterable objects, you could also use:

# requires Python >=2.4
from collections import Iterable

if isinstance(values, Iterable):
    # ....