Better Choices for django

choices.py

from collections import OrderedDict

class Choices(object):
    """
    Just like raw tuple-choices you're used to passing to django's
      choices kwarg, but better.

    :param value_label_pairs: tuple-of-pairs, like raw choices= parameters.
    :param attrs: optional attribute names to use instead of label.upper()

    If your labels are invalid attribute names (as in "Purchase Order"),
      you can supply another attrs argument (in the same order as the choices).
    """
    def __init__(self, value_label_pairs, attrs=None):
        self.pairs = OrderedDict(value_label_pairs)
        self._label_to_value = OrderedDict([(v, k) for k, v in self.pairs.items()])
        for index, (value, label) in enumerate(self.pairs.items()):
            if attrs is None:
                attr = label.upper()
            else:
                attr = attrs[index]
            setattr(self, attr, value)

    def label_to_value(self, label):
        return self._label_to_value[label]

    def value_to_label(self, value):
        return self.pairs[value]

    def offset(self, value):
        matching_index = [index for index, v in enumerate(self.pairs.values()) if v == value]
        if matching_index:
            return matching_index[0]
        else:
            raise ValueError("%s is not a valid value" % value)

    def items(self):
        return self.pairs.items()

    def __iter__(self):
        return iter(self.pairs.items())

example_usage.py

PUBLICATION_STATUSES = Choices([
    (0, 'rough'),
    (1, 'edit_ready'),
    (2, 'edited'),
    (3, 'approved'),
    (4, 'published')
])

publication_status = IntegerField(choices=PUBLICATION_STATUSES)

PUBLICATION_STATUSES.ROUGH -> 0
PUBLICATION_STATUSES.value_to_name(1) -> 'edit_ready'
PUBLICATION_STATUSES.offset(2) -> 2 # tells you what index to select based on the desired constant value.
PUBLICATION_STATUSES.items() -> [
    (0, 'rough'),
    (1, 'edit_ready'),
    (2, 'edited'),
    (3, 'approved'),
    (4, 'published')
]

tests.py

class ChoicesTestCase(SimpleTestCase):
    def test_simple_choices(self):
        pairs = (
            ('value1', 'label1'),
            ('value2', 'label2')
        )
        choices = Choices(pairs)

        self.assertEqual(choices.LABEL1, "value1")
        self.assertEqual(choices.LABEL2, "value2")
        self.assertEqual(choices.value_to_label('value1'), 'label1')
        self.assertEqual(choices.label_to_value('label1'), 'value1')

        self.assertEqual(choices.offset('label1'), 0)
        with self.assertRaises(ValueError):
            choices.offset('bad_label')

        self.assertEqual(list(choices), list(pairs),
            "Expected iter of Choices to match given pairs.")

    def test_attr_override(self):
        pairs = (
            ('value1', 'label1'),
            ('value2', 'label2')
        )
        choices = Choices(pairs, ('attr1', 'attr2'))

        self.assertEqual(choices.attr1, "value1")
        self.assertEqual(choices.attr2, "value2")
        self.assertEqual(choices.value_to_label('value1'), 'label1')
        self.assertEqual(choices.label_to_value('label1'), 'value1')

        self.assertEqual(choices.offset('label1'), 0)
        with self.assertRaises(ValueError):
            choices.offset('bad_label')

        self.assertEqual(list(choices), list(pairs),
            "Expected iter of Choices to match given pairs.")

You might prefer https://django-model-utils.readthedocs.org/en/latest/utilities.html#choices