field.py

from django.contrib.localflavor.us import us_states
from django.contrib.localflavor.us.models import USStateField
from django.db import models
from .utils import US_STATE_CHAR2FIPS, US_STATE_FIPS, US_STATE_FIPS_SHORT


class USStateFipsCode(object):
    """A US state class which includes FIPS characters and numbers."""

    def __init__(self, number):
        self.number = number
        self.code = US_STATE_FIPS_SHORT[number]
        self.name = US_STATE_FIPS[number]

    def __unicode__(self):
        return self.name

    def __repr__(self):
        return "<%s: %s>" % (self.__class__.__name__, self.code)

class InvalidFIPS(Exception):

    def __init__(self, value):
        self.value = value

    def __str__(self):
        return '%s is an invalid FIPS code' % repr(self.value)


class USStateFipsField(USStateField):

    __metaclass__ = models.SubfieldBase # Ensures to_python is always called.

    def to_python(self, value):
        if isinstance(value, USStateFipsCode):
            return value
        else:
            if value in US_STATE_CHAR2FIPS:
                value = US_STATE_CHAR2FIPS[value]
            else:
                try:
                    value = int(value)
                except TypeError:
                    raise InvalidFIPS(value)
            return USStateFipsCode(value)

    def get_prep_value(self, value):
        return value.number

utils.py

US_STATE_FIPS = {
    1: 'Alabama',
    2: 'Alaska',
    4: 'Arizona',
    5: 'Arkansas',
    6: 'California',
    8: 'Colorado',
    9: 'Connecticut',
    10: 'Delaware',
    11: 'District of Columbia',
    12: 'Florida',
    13: 'Georgia',
    15: 'Hawaii',
    16: 'Idaho',
    17: 'Illinois',
    18: 'Indiana',
    19: 'Iowa',
    20: 'Kansas',
    21: 'Kentucky',
    22: 'Louisiana',
    23: 'Maine',
    24: 'Maryland',
    25: 'Massachusetts',
    26: 'Michigan',
    27: 'Minnesota',
    28: 'Mississippi',
    29: 'Missouri',
    30: 'Montana',
    31: 'Nebraska',
    32: 'Nevada',
    33: 'New Hampshire',
    34: 'New Jersey',
    35: 'New Mexico',
    36: 'New York',
    37: 'North Carolina',
    38: 'North Dakota',
    39: 'Ohio',
    40: 'Oklahoma',
    41: 'Oregon',
    42: 'Pennsylvania',
    44: 'Rhode Island',
    45: 'South Carolina',
    46: 'South Dakota',
    47: 'Tennessee',
    48: 'Texas',
    49: 'Utah',
    50: 'Vermont',
    51: 'Virginia',
    53: 'Washington',
    54: 'West Virginia',
    55: 'Wisconsin',
    56: 'Wyoming',
    66: 'Guam',
    72: 'Puerto Rico',
    78: 'Virgin Islands',
    }

US_STATE_FIPS_SHORT = {
    1: 'AL',
    2: 'AK',
    4: 'AZ',
    5: 'AR',
    6: 'CA',
    8: 'CO',
    9: 'CT',
    10: 'DE',
    11: 'DC',
    12: 'FL',
    13: 'GA',
    15: 'HI',
    16: 'ID',
    17: 'IL',
    18: 'IN',
    19: 'IA',
    20: 'KS',
    21: 'KY',
    22: 'LA',
    23: 'ME',
    24: 'MD',
    25: 'MA',
    26: 'MI',
    27: 'MN',
    28: 'MS',
    29: 'MO',
    30: 'MT',
    31: 'NE',
    32: 'NV',
    33: 'NH',
    34: 'NJ',
    35: 'NM',
    36: 'NY',
    37: 'NC',
    38: 'ND',
    39: 'OH',
    40: 'OK',
    41: 'OR',
    42: 'PA',
    44: 'RI',
    45: 'SC',
    46: 'SD',
    47: 'TN',
    48: 'TX',
    49: 'UT',
    50: 'VT',
    51: 'VA',
    53: 'WA',
    54: 'WV',
    55: 'WI',
    56: 'WY',
    66: 'GU',
    72: 'PR',
    78: 'VI',
    }

US_STATE_CHAR2FIPS = dict([v,k] for k, v in US_STATE_FIPS_SHORT.iteritems())