Add "Any" filter to ChoicesField

[cvk77]

The ChoicesField currently doesn't provide an "Any" or "Unknown" filter entry, so as soon as a ChoiceField is added to a search form, the user has to always select an entry.

I currently workaround this by adding an empty filter in the Filter's constructor, but it would be great if there could be an easier way to achieve this:

class NicerFilterSet(django_filters.FilterSet):

def __init__(self, *args, **kwargs):
    super(NicerFilterSet, self).__init__(*args, **kwargs)

    for name, field in self.filters.iteritems():
        if isinstance(field, ChoiceFilter):
            # Add "Any" entry to choice fields.
            field.extra['choices'] = tuple([("", "Any"), ] + list(field.extra['choices']))`

[ngottlieb]

Nice -- thanks for the workaround. Agreed that it's a pretty common requirement for a search/filter form.

[apollo13]

Could you guys rework that into a pull request with docs and tests? Thx!

[carltongibson]

@57even commented in #172. I'm closing that and pasting it here to keep everything in one place:

I think #45 is a great improvement but empty values gets the option "None" which is equivalent to no filter condition (instead of empty).

How could this be solved? I think the empty values should be completely ignored in AllValuesFilter.

[carltongibson]

Related to #36

[carltongibson]

Closing this in favour of #261

[paulhauner]

Here's a Python3 compatible version of the original work-around by @cvk77 (see top of thread)

class NicerFilterSet(django_filters.FilterSet):

def __init__(self, *args, **kwargs):
  super(NicerFilterSet, self).__init__(*args, **kwargs)

  for name, field in self.filters.items():
    if isinstance(field, ChoiceFilter):
      # Add "Any" entry to choice fields.
      field.extra['choices'] = tuple([("", "Any"), ] + list(field.extra['choices']))

Changes:
self.filters.iteritems() was changed to self.filters.items()