Working with CHOICES tuples

Django provides no easy way for doing lookup in CHOICES tuples other than get_FIELD_display() in a database context. For using CHOICES tuples without a database and for doing reverse lookup this library has two functions: get_choice_name and get_choice_value. Furthermore there is a function to ‘translate’ a CHOICES tuple with groups to a ‘flat’ tuple. For the following examples, these CHOICES tuples are used:

SIMPLE_CHOICES = (
        (0, 'zero'),
        (1, 'one'),
        (2, 'two'),
        (3, 'three'),
)
GROUPED_CHOICES = (
        ('group1', (
                (0, 'zero'),
                (1, 'one'),
        )),
        ('group2', (
            (2, 'two'),
            (3, 'three'),
        )),
        ('nogroup', 'four'),
)

>>> import djangoutillib.utils as du
>>> du.get_choice_name(SIMPLE_CHOICES, 2)
two
>>> du.get_choice_name(SIMPLE_CHOICES, 5)
KeyError: 5
>>> du.get_choice_name(GROUPED_CHOICES, 3)
three
>>> du.get_choice_name(GROUPED_CHOICES, 'nogroup')
four

>>> import djangoutillib.utils as du
>>> du.get_choice_value(SIMPLE_CHOICES, 'two')
2
>>> du.get_choice_value(GROUPED_CHOICES, 'three')
3
>>> du.get_choice_value(GROUPED_CHOICES, 'four')
nogroup
>>> du.get_choice_value(GROUPED_CHOICES, 'five')
KeyError: 'five'

>>> import djangoutillib.utils as du
>>> du.degroup_choices(GROUPED_CHOICES)
[(0, 'zero'), (1, 'one'), (2, 'two'), (3, 'three'), ('nogroup', 'four')]