python - Django view - exclude in queryset? -

i have problem: after creating new world, (all countries automatically assigned every new world) user choose 1 country showed on top of site , can't delete country. how this?

class country(models.model):     name = models.charfield(verbose_name="name of country", max_length=100, default="australia")     number = models.integerfield(verbose_name="number of country", default="1")      def __unicode__(self):         return self.name  class world(models.model):     country = models.manytomanyfield(country)     name = models.charfield(verbose_name="new map", max_length=100)      def __unicode__(self):         return self.name 

now have this: after creating world user redirecting new_my_world, there should choose country , redirected site my_world view can delete countires expect one. how this? views.py

def new_my_world(request, pk):     world = get_object_or_404(world, pk=pk)     return render(request, 'game/new_my_world.html', {'world': world})  def my_world(request, pk):     world = get_object_or_404(world.objects.exclude(??, pk=pk)     return render(request, 'game/my_world.html', {'world': world})  def choose_country(request, world_pk, country_pk):     world = get_object_or_404(world, pk=pk)     country = get_object_or_404(country, pk=pk)     return redirect('my_world', pk=world.pk) 

i know in my_world view there's should exclude (excluding coosen country) don't know how connect it.

edit

url:

  url(r'^world/(?p<pk>[%&+ \w]+)/(?p<country_pk>[%&+ \w]+)/$', views.my_world, name='my_world'), 

edit2:

how create url my_world? after creating new world,when click on first country choose error

with url:

url(r'^world/(?p<pk>[%&+ \w]+)/(?p<country_pk>[%&+ \w]+)/$', views.my_world, name='my_world'),  page not found (404) request method:     request url:    http://127.0.0.1:8000/world/22/9/ raised by:  game.views.my_world  no world matches given query. 

i fix choose_country following:

def choose_country(request, world_pk, country_pk):     world = get_object_or_404(world, pk=world_pk)     country = get_object_or_404(country, pk=country_pk)     return redirect('my_world', pk=world.pk, country_pk = country.id) 

then in my_world function should changed this:

def my_world(request, pk, country_pk):     world = get_object_or_404(world.objects.exclude(country__id = country_pk), pk=pk)     return render(request, 'game/my_world.html', {'world': world}) 

edit 1 if country same of country of world, above get_object_or_404(world.objects.exclude(country__id = country_pk), pk=pk) sure return not found. suggest my_world follows:

def my_world(request, pk, country_pk):         world = get_object_or_404(world, pk=pk)         countries = get_object_or_404(country.object.exclude(pk=country_pk))         return render(request, 'game/my_world.html', {'world': world, 'countries': countries})