This is my music\urls.py code:-

     #/music/
url(r'^/$', views.index, name='index'),#/music/712/
url(r'^(?P<album_id>[0-9]+)/$', views.detail, name='detail'),

And this is my views.py code:-

def index(request):
return HttpResponse("This will be a list of all the albums")def detail(request, album_id):
return HttpResponse("Details for album id: " + str(album_id))

Now why am I getting a Page not found(404) error whenever I try to open this link 127.0.0.1:8000/music/2/ in browser

ERROR MESSAGE:-

Page not found (404) Request Method: GET Request URL: http://127.0.0.1:8000/music/2/ Using the URLconf defined in website.urls, Django tried these URL patterns, in this order: ^admin/ ^music ^/$ [name='index'] ^music ^(?P[0-9]+)/$ [name='detail'] The current URL, music/2/, didn't match any of these.

Error message

Your url patterns are missing the slash between music and <album_id> - currently, they would match /music2/ instead of /music/2/.

Add the missing slash to the url pattern that includes the music urls:

url('^music/', include('music.urls')),

Then remove the slash from your index pattern to avoid a double slash.

url(r'^$', views.index, name='index'),