django-extended-choices
aims to provide a better and more readable
way of using choices in Django.
You can install directly via pip (since version 0.3
):
$ pip install django-extended-choices
Or from the Github repository (master
branch by default):
$ git clone git://github.com/twidi/django-extended-choices.git $ cd django-extended-choices $ sudo python setup.py install
The aim is to replace this:
STATE_ONLINE = 1
STATE_DRAFT = 2
STATE_OFFLINE = 3
STATE_CHOICES = (
(STATE_ONLINE, 'Online'),
(STATE_DRAFT, 'Draft'),
(STATE_OFFLINE, 'Offline'),
)
STATE_DICT = dict(STATE_CHOICES)
class Content(models.Model):
title = models.CharField(max_length=255)
content = models.TextField()
state = models.PositiveSmallIntegerField(choices=STATE_CHOICES, default=STATE_DRAFT)
def __unicode__(self):
return u'Content "%s" (state=%s)' % (self.title, STATE_DICT[self.state])
print(Content.objects.filter(state=STATE_ONLINE))
by this:
from extended_choices import Choices
STATES = Choices(
('ONLINE', 1, 'Online'),
('DRAFT', 2, 'Draft'),
('OFFLINE', 3, 'Offline'),
)
class Content(models.Model):
title = models.CharField(max_length=255)
content = models.TextField()
state = models.PositiveSmallIntegerField(choices=STATES, default=STATES.DRAFT)
def __unicode__(self):
return u'Content "%s" (state=%s)' % (self.title, STATES.for_value(self.state).display)
print(Content.objects.filter(state=STATES.ONLINE))
As you can see there is only one declaration for all states with, for each state, in order:
- the pseudo-constant name which can be used (
STATES.ONLINE
replaces the previousSTATE_ONLINE
) - the value to use in the database - which could equally be a string
- the name to be displayed - and you can wrap the text in
ugettext_lazy()
if you need i18n
And then, you can use:
STATES
, orSTATES.choices
, to use withchoices=
in fields declarationsSTATES.for_constant(constant)
, to get the choice entry from the constant nameSTATES.for_value(constant)
, to get the choice entry from the key used in databaseSTATES.for_display(constant)
, to get the choice entry from the displayable value (can be useful in some case)
Each choice entry obtained by for_constant
, for_value
and for_display
return a tuple as
given to the Choices
constructor, but with additional attributes:
>>> entry = STATES.for_constant('ONLINE')
>>> entry == ('ONLINE', 1, 'Online')
True
>>> entry.constant
'ONLINE'
>>> entry.value
1
>>> entry.display
'Online'
These attributes are chainable (with a weird example to see chainability):
>>> entry.constant.value
1
>>> entry.constant.value.value.display.constant.display
'Online'
To allow this, we had to remove support for None
values. Use empty strings instead.
Note that constants can be accessed via a dict key (STATES['ONLINE']
for example) if
you want to fight your IDE that may warn you about undefined attributes.
You can check whether a value is in a Choices
object directly:
>>> 1 in STATES
True
>>> 42 in STATES
False
You can even iterate on a Choices
objects to get choices as seen by Django:
>>> for choice in STATES:
... print(choice)
(1, 'Online')
(2, 'Draf')
(3, 'Offline')
To get all choice entries as given to the Choices
object, you can use the entries
attribute:
>>> for choice_entry in STATES.entries:
... print(choice_entry)
('ONLINE', 1, 'Online'),
('DRAFT', 2, 'Draft'),
('OFFLINE', 3, 'Offline'),
Or the following dicts, using constants, values or display names, as keys, and the matching choice entry as values:
STATES.constants
STATES.values
STATES.displays
>>> STATES.constants['ONLINE'] is STATES.for_constant('ONLINE')
True
>>> STATES.values[2] is STATES.for_value(2)
True
>>> STATES.displays['Offline'] is STATES.for_display('Offline')
True
If you want these dicts to be ordered, you can pass the dict class to use to the
Choices
constructor:
from collections import OrderedDict
STATES = Choices(
('ONLINE', 1, 'Online'),
('DRAFT', 2, 'Draft'),
('OFFLINE', 3, 'Offline'),
dict_class = OrderedDict
)
Since version 1.1
, the new OrderedChoices
class is provided, that is exactly that:
a Choices
using OrderedDict
by default for dict_class
.
You can check if a constant, value, or display name exists:
>>> STATES.has_constant('ONLINE')
True
>>> STATES.has_value(1)
True
>>> STATES.has_display('Online')
True
You can create subsets of choices within the same Choices
instance:
>>> STATES.add_subset('NOT_ONLINE', ('DRAFT', 'OFFLINE',))
>>> STATES.NOT_ONLINE
(2, 'Draft')
(3, 'Offline')
Now, STATES.NOT_ONLINE
is a real Choices
instance, with a subset of the main STATES
constants.
You can use it to generate choices for when you only want a subset of choices available:
offline_state = models.PositiveSmallIntegerField(
choices=STATES.NOT_ONLINE,
default=STATES.DRAFT
)
As the subset is a real Choices
instance, you have the same attributes and methods:
>>> STATES.NOT_ONLINE.for_constant('OFFLINE').value
3
>>> STATES.NOT_ONLINE.for_value(1).constant
Traceback (most recent call last):
...
KeyError: 3
>>> list(STATES.NOT_ONLINE.constants.keys())
['DRAFT', 'OFFLINE]
>>> STATES.NOT_ONLINE.has_display('Online')
False
You can create as many subsets as you want, reusing the same constants if needed:
STATES.add_subset('NOT_OFFLINE', ('ONLINE', 'DRAFT'))
If you want to check membership in a subset you could do:
def is_online(self):
# it's an example, we could have just tested with STATES.ONLINE
return self.state not in STATES.NOT_ONLINE_DICT
You can add choice entries in many steps using add_choices
, possibly creating subsets at
the same time.
To construct the same Choices
as before, we could have done:
STATES = Choices()
STATES.add_choices(
('ONLINE', 1, 'Online)
)
STATES.add_choices(
('DRAFT', 2, 'Draft'),
('OFFLINE', 3, 'Offline'),
name='NOT_ONLINE'
)
You can also pass the argument
to the Choices
constructor to create a subset with all
the choices entries added at the same time (it will call add_choices
with the name and the
entries)
The list of existing subset names is in the subsets
attributes of the parent Choices
object.
If you want a subset of the choices but not save it in the original Choices
object, you can
use extract_subset
instead of add_subset
>>> subset = STATES.extract_subset('DRAFT', 'OFFLINE')
>>> subset
(2, 'Draft')
(3, 'Offline')
As for a subset created by add_subset
, you have a real Choices
object, but not accessible
from the original Choices
object.
Note that in extract_subset
, you pass the strings directly, not in a list/tuple as for the
second argument of add_subset
.
- You also have a very basic field (
NamedExtendedChoiceFormField`
) inextended_choices.fields
which accept constant names instead of values - Feel free to read the source to learn more about this little Django app.
- You can declare your choices where you want. My usage is in the
models.py
file, just before the class declaration.
The version 1.0
provided a totally new API, and compatibility with the previous one
(0.4.1
) was removed in 1.1
. The last version with the compatibility was 1.0.7
.
If you need this compatibility, you can use a specific version by pinning it in your requirements.
Available under the BSD License. See the LICENSE
file included
Of course! We support python 2.6
, 2.7
, 3.3
, 3.4
and 3.5
, for Django version
1.5.x
to 1.10.x
, respecting the Django matrix (except for python 2.5
and 3.2
which are not supported by django-extended-choices
)
To run tests from the code source, create a virtualenv or activate one, install Django, then:
python -m extended_choices.tests
We also provides some quick doctests in the code documentation. To execute them:
python -m extended_choices.choices
Note: the doctests will work only in python version not display u prefix for strings.
The source code is available on Github.
If you want to participate in the development of this library, you'll need Django
installed in your virtualenv. If you don't have it, simply run:
pip install -r requirements-dev.txt
Don't forget to run the tests ;)
Feel free to propose a pull request on Github!
A few minutes after your pull request, tests will be executed on TravisCi for all the versions of python and Django we support.
You can find the documentation on ReadTheDoc
To update the documentation, you'll need some tools:
pip install -r requirements-makedoc.txt
Then go to the docs
directory, and run:
make html
Written by Stephane "Twidi" Angel <s.angel@twidi.com> (http://twidi.com), originally for http://www.liberation.fr