Removes PHP references

Note ``{{ article.pub_date|date:"F j, Y" }}`` uses a Unix-style "pipe" (the "|"

character). This is called a template filter, and it's a way to filter the value

of a variable. In this case, the date filter formats a Python datetime object in

the given format (as found in PHP's date function; yes, there is one good idea

in PHP).

the given format (as found in PHP's date function).

You can chain together as many filters as you'd like. You can write custom

filters. You can write custom template tags, which run custom Python code behind

.. admonition:: Where should this code live?

    If your background is in PHP, you're probably used to putting code under the

    Web server's document root (in a place such as ``/var/www``). With Django,

    you don't do that. It's not a good idea to put any of this Python code

    within your Web server's document root, because it risks the possibility

    that people may be able to view your code over the Web. That's not good for

    security.

    If your background is in plain old PHP (with no use of modern frameworks),

    you're probably used to putting code under the Web server's document root

    (in a place such as ``/var/www``). With Django, you don't do that. It's

    not a good idea to put any of this Python code within your Web server's

    document root, because it risks the possibility that people may be able

    to view your code over the Web. That's not good for security.

    Put your code in some directory **outside** of the document root, such as

    :file:`/home/mycode`.

match a sequence of digits (i.e., a number).

Because the URL patterns are regular expressions, there really is no limit on

what you can do with them. And there's no need to add URL cruft such as ``.php``

-- unless you have a sick sense of humor, in which case you can do something

like this::

what you can do with them. And there's no need to add URL cruft such as

``.html`` -- unless you want to, in which case you can do something like

this::

    (r'^polls/latest\.php$', 'polls.views.index'),

    (r'^polls/latest\.html$', 'polls.views.index'),

But, don't do that. It's silly.

presentation-related logic -- and that's it. The template system shouldn't

support functionality that goes beyond this basic goal.

If we wanted to put everything in templates, we'd be using PHP. Been there,

done that, wised up.

Discourage redundancy

---------------------

.. admonition:: Philosophy

    If you have a background in programming, or if you're used to languages

    like PHP which mix programming code directly into HTML, you'll want to

    bear in mind that the Django template system is not simply Python embedded

    into HTML. This is by design: the template system is meant to express

    which mix programming code directly into HTML, you'll want to bear in

    mind that the Django template system is not simply Python embedded into

    HTML. This is by design: the template system is meant to express

    presentation, not program logic.

    The Django template system provides tags which function similarly to some