简体   繁体   中英

Using __str__() method in Django on Python 2

I am Learning Django using the Django project tutorial . Since I use python 2.7 I am unable to implement the following in python 2.7:

from django.db import models

class Question(models.Model):
# ...
    def __str__(self):              # __unicode__ on Python 2
        return self.question_text

class Choice(models.Model):
# ...
    def __str__(self):              # __unicode__ on Python 2
        return self.choice_text

To keep the code compatible between py2 and py3, a better way is to use the decorator python_2_unicode_compatible . This way you can keep the str method:

from django.db import models
from django.utils.encoding import python_2_unicode_compatible

@python_2_unicode_compatible
class Question(models.Model):
# ...
    def __str__(self):              # __unicode__ on Python 2
        return self.question_text

@python_2_unicode_compatible
class Choice(models.Model):
# ...
    def __str__(self):              # __unicode__ on Python 2
        return self.choice_text

Reference: https://docs.djangoproject.com/en/1.8/topics/python3/#str-and-unicode-methods

Django provides a simple way to define str () and unicode () methods that work on Python 2 and 3: you must define a str () method returning text and to apply the python_2_unicode_compatible() decorator.

...

This technique is the best match for Django's porting philosophy.

Yes you can, you just replace __str__ with __unicode__ , as the comment states:

class Question(models.Model):
# ...
    def __unicode__(self):
        return self.question_text

class Choice(models.Model):
# ...
    def __unicode__(self):
        return self.choice_text

Further down that section you'll find a bit of explanation:

__str__ or __unicode__?

On Python 3, it's easy, just use __str__() .

On Python 2, you should define __unicode__() methods returning unicode values instead. Django models have a default __str__() method that calls __unicode__() and converts the result to a UTF-8 bytestring. This means that unicode(p) will return a Unicode string, and str(p) will return a bytestring, with characters encoded as UTF-8. Python does the opposite: object has a __unicode__ method that calls __str__ and interprets the result as an ASCII bytestring. This difference can create confusion.

The question_text and choice_text attributes return Unicode values already.

The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.

 
粤ICP备18138465号  © 2020-2024 STACKOOM.COM