Example
To create a human-readable presentation of a model object you need to implement Model.__str__() method (or Model.__unicode__() on python2). This method will be called whenever you call str() on a instance of your model (including, for instance, when the model is used in a template). Here's an example:
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Create a book model.
# your_app/models.py from django.db import models class Book(models.Model): name = models.CharField(max_length=50) author = models.CharField(max_length=50) -
Create an instance of the model, and save it in the database:
>>> himu_book = Book(name='Himu Mama', author='Humayun Ahmed') >>> himu_book.save() -
Execute
print()on the instance:>>> print(himu_book) <Book: Book object>
<Book: Book object>, the default output, is of no help to us. To fix this, let's add a __str__ method.
from django.utils.encoding import python_2_unicode_compatible
@python_2_unicode_compatible
class Book(models.Model):
name = models.CharField(max_length=50)
author = models.CharField(max_length=50)
def __str__(self):
return '{} by {}'.format(self.name, self.author)
Note the python_2_unicode_compatible decorator is needed only if you want your code to be compatible with python 2. This decorator copies the __str__ method to create a __unicode__ method. Import it from django.utils.encoding.
Now if we call the print function the book instance again:
>>> print(himu_book)
Himu Mama by Humayun Ahmed
Much better!
The string representation is also used when the model is used in a ModelForm for ForeignKeyField and ManyToManyField fields.
