Reverse for with arguments and keyword arguments not found

Question

Caught an exception while rendering        Reverse for  products views  filter by led  with arguments      and   keyword arguments      not found    I was able to successfully import products views filter by led from the shell and it worked so the path should be correct   Here is the urls py      r  led-tv     filter by led      This is where the error is being generated     href     url products views filter by led     gt    Which I can t understand because this works fine from the same file        url products views lcd screen size screen size 50      Here is the function definition     def filter by led request     I don t understand why Django would think that the function would not be able to find the Reverse for that function   I deleted all the   pyc files and restarted Apache   What am I doing wrong

User · Accepted Answer

There are 3 things I can think of off the top of my head:

Just used named urls, it's more robust and maintainable anyway

Try using django.core.urlresolvers.reverse at the command line for a (possibly) better error

>>> from django.core.urlresolvers import reverse
>>> reverse('products.views.filter_by_led')

Check to see if you have more than one url that points to that view

User · Answer

I don t think you need the trailing slash in the URL entry  Ie  put this instead    r  led-tv    filter by led      This is assuming you have trailing slashes enabled  which is the default

User · Answer

I had a similar problem and the solution was in the right use of the      end-of-string  character   My main url py looked like this  notice the   character    urlpatterns     url r  admin    include admin site urls     url r      include  card purchase urls          and my url py for my card purchases app said   urlpatterns     url r      views index  name  index    url r  purchase     views purchase detail  name  purchase       I used the     twice  So a simple change worked   urlpatterns     url r  admin    include admin site urls     url r  cp    include  card purchase urls          Notice the change in the second url  My url py for my card purchases app looks like this   urlpatterns     url r      views index  name  index    url r  purchase     views purchase detail  name  purchase       Apart from this  I can confirm that quotes around named urls are crucial

User · Answer

Shell calls to reverse  as mentioned above  are very good to debug these problems  but there are two critical conditions    you must supply arguments that matches whatever arguments the view needs  these arguments must match regexp patterns    Yes  it s logical  Yes  it s also confusing because reverse will only throw the exception and won t give you any further hints   An example of URL pattern   url r  cookies   P lt hostname gt          P lt url id gt  d        register site views show cookies   name  show cookies      And then what happens in shell    gt  gt  gt  from register site views import show cookies  gt  gt  gt  reverse show cookies  NoReverseMatch  Reverse for  register site views show cookies  with arguments      and keyword arguments      not found    It doesn t work because I supplied no arguments    gt  gt  gt  reverse  show cookies   kwargs   url id  123  hostname    aaa      cookies aaa 123    Now it worked  but      gt  gt  gt  reverse  show cookies   kwargs   url id   x   hostname    www dupa com    NoReverseMatch  Reverse for  show cookies  with arguments      and keyword arguments    url id    x    hostname    www dupa com    not found    Now it didn t work because url id didn t match the regexp  expected numeric  supplied string    You can use reverse with both positional arguments and keyword arguments  The syntax is   reverse viewname  urlconf None  args None  kwargs None  prefix None  current app None    As it comes to the url template tag  there s funny thing about it  Django documentation gives example of using quoted view name         url  news views year archive  yearvar      So I used it in a similar way in my HTML template         url  show cookies  hostname u hostname url id u pk      But this didn t work for me  But the exception message gave me a hint of what could be wrong - note the double single quotes around view name      Reverse for   show cookies   with arguments      It started to work when I removed the quotes         url show cookies hostname u hostname url id u pk      And this is confusing

User · Answer

You need single quotes around the view name     url  viewname       instead of     url viewname

User · Answer

In case it helps someone  I had a similar issue and the error was because of two reasons    Not using the app s namespace before the url name     url  app name url name      Missing single quotes around the url name  as pointed out here by Charlie

User · Answer

url  polls create  poll id

[python] Reverse for '*' with arguments '()' and keyword arguments '{}' not found

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