When Django accepts an incoming request, one of the first things it does is that it looks at the URL and tries to match it against a group of URL patterns. In order to identify patterns, Django uses regular expressions to see if the URLs follow a known format.

Consider these URLs:

http://localhost:8000/press/detail/1/
http://localhost:8000/press/detail/2/

These URLs appear to follow a pattern that they start with press/detail/ and end with a number that represents the ID of a press release. (Recall that we don't work with the domain name portion of the URL. Django takes care of this automatically for us and just sends us everything that follows the domain name.)

With this pattern, we can add a new line to our mycompany/urls.py file:

from django.conf.urls.defaults import *
from django.contrib import admin

admin.autodiscover()

urlpatterns = patterns('',
    (r'^admin/(.*)', admin.site.root),
    (r'^press/detail/\d+/$', 'mycompany.press.views.detail'),
)

If you're not...