url.py中的配置问题

urlpatterns = [
    url(r'^add$', calc_views.add, name='add'), 
    url(r'^admin/', admin.site.urls),
]
当初就是这么写的 。 然后访问xxx/

是这么提示的:

Page not found (404)

Request Method:	GET
Request URL:	http://127.0.0.1:8000/

Using the URLconf defined in add.urls, Django tried these URL patterns, in this order:

1. ^a$ [name='q']
2. ^admin/

The empty path didn't match any of these.

You're seeing this error because you have DEBUG = True in your Django settings file. Change that to False, and Django will display a standard 404 page.

……

不多说了。

改回来

url(r'^$', calc_views.add, name='q'),#根目录

url(r'^a$', calc_views.add, name='q'), xx/a