Fixed #21951 -- Updated docs to use __str__ for Python 3

Thanks Tim Graham for the report and recommendations
This commit is contained in:
Alasdair Nicol 2014-02-09 11:38:13 +00:00 committed by Tim Graham
parent c3434fed5b
commit 8aa1efff6d
20 changed files with 71 additions and 72 deletions

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@ -817,13 +817,13 @@ smoothly:
a field that's similar to what you want and extend it a little bit,
instead of creating an entirely new field from scratch.
2. Put a ``__str__()`` or ``__unicode__()`` method on the class you're
2. Put a ``__str__()`` (``__unicode__()`` on Python 2) method on the class you're
wrapping up as a field. There are a lot of places where the default
behavior of the field code is to call
:func:`~django.utils.encoding.force_text` on the value. (In our
examples in this document, ``value`` would be a ``Hand`` instance, not a
``HandField``). So if your ``__unicode__()`` method (``__str__()`` on
Python 3) automatically converts to the string form of your Python object,
``HandField``). So if your ``__str__()`` method (``__unicode__()`` on
Python 2) automatically converts to the string form of your Python object,
you can save yourself a lot of work.

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@ -727,7 +727,7 @@ Save these changes and start a new Python interactive shell by running
>>> from polls.models import Question, Choice
# Make sure our __unicode__() addition worked.
# Make sure our __str__() addition worked.
>>> Question.objects.all()
[<Question: What's up?>]

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@ -57,8 +57,7 @@ simple news application with an ``Article`` model::
body = models.TextField()
status = models.CharField(max_length=1, choices=STATUS_CHOICES)
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.title
A common task we might perform with a model like this is to update an

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@ -512,7 +512,7 @@ subclass::
list_display = ('first_name', 'last_name')
If you don't set ``list_display``, the admin site will display a single
column that displays the ``__unicode__()`` (``__str__()`` on Python 3)
column that displays the ``__str__()`` (``__unicode__()`` on Python 2)
representation of each object.
You have four possible values that can be used in ``list_display``:
@ -563,7 +563,7 @@ subclass::
A few special cases to note about ``list_display``:
* If the field is a ``ForeignKey``, Django will display the
``__unicode__()`` (``__str__()`` on Python 3) of the related object.
``__str__()`` (``__unicode__()`` on Python 2) of the related object.
* ``ManyToManyField`` fields aren't supported, because that would
entail executing a separate SQL statement for each row in the table.
@ -626,11 +626,11 @@ subclass::
list_display = ('name', 'born_in_fifties')
* The ``__str__()`` and ``__unicode__()`` methods are just as valid in
``list_display`` as any other model method, so it's perfectly OK to
do this::
* The ``__str__()`` (``__unicode__()`` on Python 2) method is just
as valid in ``list_display`` as any other model method, so it's
perfectly OK to do this::
list_display = ('__unicode__', 'some_other_field')
list_display = ('__str__', 'some_other_field')
* Usually, elements of ``list_display`` that aren't actual database
fields can't be used in sorting (because Django does all the sorting

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@ -259,8 +259,7 @@ A simple example is a tagging system, which might look like this::
object_id = models.PositiveIntegerField()
content_object = GenericForeignKey('content_type', 'object_id')
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.tag
A normal :class:`~django.db.models.ForeignKey` can only "point

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@ -65,7 +65,7 @@ of using ``ogrinspect`` :ref:`in the tutorial <ogrinspect-intro>`.
.. django-admin-option:: --name-field <name_field>
Generates a ``__unicode__`` routine (``__str__`` on Python 3) on the model
Generates a ``__str__`` routine (``__unicode__`` on Python 2) on the model
that will return the given field name.
.. django-admin-option:: --no-imports

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@ -61,8 +61,7 @@ Example
poly = models.PolygonField(srid=4269) # we want our model in a different SRID
objects = models.GeoManager()
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return 'Name: %s' % self.name
3. Use :class:`LayerMapping` to extract all the features and place them in the

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@ -244,8 +244,7 @@ model to represent this data::
objects = models.GeoManager()
# Returns the string representation of the model.
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.name
Please note two important things:

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@ -653,16 +653,16 @@ Customizing the error list format
By default, forms use ``django.forms.utils.ErrorList`` to format validation
errors. If you'd like to use an alternate class for displaying errors, you can
pass that in at construction time (replace ``__unicode__`` by ``__str__`` on
Python 3)::
pass that in at construction time (replace ``__str__`` by ``__unicode__`` on
Python 2)::
>>> from django.forms.utils import ErrorList
>>> class DivErrorList(ErrorList):
... def __unicode__(self):
... def __str__(self): # __unicode__ on Python 2
... return self.as_divs()
... def as_divs(self):
... if not self: return u''
... return u'<div class="errorlist">%s</div>' % ''.join([u'<div class="error">%s</div>' % e for e in self])
... if not self: return ''
... return '<div class="errorlist">%s</div>' % ''.join(['<div class="error">%s</div>' % e for e in self])
>>> f = ContactForm(data, auto_id=False, error_class=DivErrorList)
>>> f.as_p()
<div class="errorlist"><div class="error">This field is required.</div></div>
@ -687,8 +687,8 @@ lazy developers -- they're not the only way a form object can be displayed.
Used to display HTML or access attributes for a single field of a
:class:`Form` instance.
The ``__unicode__()`` and ``__str__()`` methods of this object displays
the HTML for this field.
The ``__str__()`` (``__unicode__`` on Python 2) method of this
object displays the HTML for this field.
To retrieve a single ``BoundField``, use dictionary lookup syntax on your form
using the field's name as the key::

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@ -1047,7 +1047,7 @@ objects (in the case of ``ModelMultipleChoiceField``) into the
initial value, no empty choice is created (regardless of the value
of ``empty_label``).
The ``__unicode__`` (``__str__`` on Python 3) method of the model will be
The ``__str__`` (``__unicode__`` on Python 2) method of the model will be
called to generate string representations of the objects for use in the
field's choices; to provide customized representations, subclass
``ModelChoiceField`` and override ``label_from_instance``. This method will

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@ -463,9 +463,29 @@ the conversion to string objects when required.
.. method:: Model.__str__()
The ``__str__()`` method is called whenever you call ``str()`` on an object. The main use for this method directly inside Django is when the ``repr()`` output of a model is displayed anywhere (for example, in debugging output).
Thus, you should return a nice, human-readable string for the object's
``__str__()``. It isn't required to put ``__str__()`` methods everywhere if you have sensible :meth:`~Model.__unicode__()` methods.
The ``__str__()`` method is called whenever you call ``str()`` on an
object. In Python 3, Django uses ``str(obj)`` in a number of
places. Most notably, to display an object in the Django admin site
and as the value inserted into a template when it displays an
object. Thus, you should always return a nice, human-readable
representation of the model from the ``__str__()`` method.
For example::
from django.db import models
class Person(models.Model):
first_name = models.CharField(max_length=50)
last_name = models.CharField(max_length=50)
def __str__(self):
return '%s %s' % (self.first_name, self.last_name)
In Python 2, the main use of ``__str__`` directly inside Django is
when the ``repr()`` output of a model is displayed anywhere (for
example, in debugging output). It isn't required to put ``__str__()``
methods everywhere if you have sensible :meth:`~Model.__unicode__()`
methods.
The previous :meth:`~Model.__unicode__()` example could be similarly written
using ``__str__()`` like this::

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@ -812,17 +812,16 @@ For example, suppose you have these models::
name = models.CharField(max_length=50)
toppings = models.ManyToManyField(Topping)
# On Python 3: def __str__(self):
def __unicode__(self):
return u"%s (%s)" % (self.name, u", ".join([topping.name
for topping in self.toppings.all()]))
def __str__(self): # __unicode__ on Python 2
return "%s (%s)" % (self.name, ", ".join([topping.name
for topping in self.toppings.all()]))
and run::
>>> Pizza.objects.all()
[u"Hawaiian (ham, pineapple)", u"Seafood (prawns, smoked salmon)"...
["Hawaiian (ham, pineapple)", "Seafood (prawns, smoked salmon)"...
The problem with this is that every time ``Pizza.__unicode__()`` asks for
The problem with this is that every time ``Pizza.__str__()`` asks for
``self.toppings.all()`` it has to query the database, so
``Pizza.objects.all()`` will run a query on the Toppings table for **every**
item in the Pizza ``QuerySet``.

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@ -984,8 +984,7 @@ authentication app::
# The user is identified by their email address
return self.email
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.email
def has_perm(self, perm, obj=None):

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@ -89,8 +89,7 @@ We'll be using these models::
class Meta:
ordering = ["-name"]
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.name
class Author(models.Model):
@ -99,8 +98,7 @@ We'll be using these models::
email = models.EmailField()
headshot = models.ImageField(upload_to='author_headshots')
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.name
class Book(models.Model):

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@ -16,8 +16,7 @@ objects, and a ``Publication`` has multiple ``Article`` objects:
class Publication(models.Model):
title = models.CharField(max_length=30)
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.title
class Meta:
@ -27,8 +26,7 @@ objects, and a ``Publication`` has multiple ``Article`` objects:
headline = models.CharField(max_length=100)
publications = models.ManyToManyField(Publication)
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.headline
class Meta:

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@ -15,17 +15,15 @@ To define a many-to-one relationship, use :class:`~django.db.models.ForeignKey`.
last_name = models.CharField(max_length=30)
email = models.EmailField()
# On Python 3: def __str__(self):
def __unicode__(self):
return u"%s %s" % (self.first_name, self.last_name)
def __str__(self): # __unicode__ on Python 2
return "%s %s" % (self.first_name, self.last_name)
class Article(models.Model):
headline = models.CharField(max_length=100)
pub_date = models.DateField()
reporter = models.ForeignKey(Reporter)
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.headline
class Meta:

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@ -16,26 +16,23 @@ In this example, a ``Place`` optionally can be a ``Restaurant``:
name = models.CharField(max_length=50)
address = models.CharField(max_length=80)
# On Python 3: def __str__(self):
def __unicode__(self):
return u"%s the place" % self.name
def __str__(self): # __unicode__ on Python 2
return "%s the place" % self.name
class Restaurant(models.Model):
place = models.OneToOneField(Place, primary_key=True)
serves_hot_dogs = models.BooleanField()
serves_pizza = models.BooleanField()
# On Python 3: def __str__(self):
def __unicode__(self):
return u"%s the restaurant" % self.place.name
def __str__(self): # __unicode__ on Python 2
return "%s the restaurant" % self.place.name
class Waiter(models.Model):
restaurant = models.ForeignKey(Restaurant)
name = models.CharField(max_length=50)
# On Python 3: def __str__(self):
def __unicode__(self):
return u"%s the waiter at %s" % (self.name, self.restaurant)
def __str__(self): # __unicode__ on Python 2
return "%s the waiter at %s" % (self.name, self.restaurant)
What follows are examples of operations that can be performed using the Python
API facilities.

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@ -417,16 +417,14 @@ something like this::
class Person(models.Model):
name = models.CharField(max_length=128)
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.name
class Group(models.Model):
name = models.CharField(max_length=128)
members = models.ManyToManyField(Person, through='Membership')
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.name
class Membership(models.Model):

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@ -23,16 +23,14 @@ models, which comprise a Weblog application:
name = models.CharField(max_length=100)
tagline = models.TextField()
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.name
class Author(models.Model):
name = models.CharField(max_length=50)
email = models.EmailField()
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.name
class Entry(models.Model):
@ -46,8 +44,7 @@ models, which comprise a Weblog application:
n_pingbacks = models.IntegerField()
rating = models.IntegerField()
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.headline
Creating objects

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@ -162,8 +162,7 @@ Consider this set of models::
title = models.CharField(max_length=3, choices=TITLE_CHOICES)
birth_date = models.DateField(blank=True, null=True)
# On Python 3: def __str__(self):
def __unicode__(self):
def __str__(self): # __unicode__ on Python 2
return self.name
class Book(models.Model):