class Length(expression, **extra) [source]
Accepts a single text field or expression and returns the number of characters the value has. If the expression is null, then the length will also be null.
Usage example:
1 2 3 4 5 6 7 8 | >>> # Get the length of the name and goes_by fields>>> from django.db.models.functions import Length>>> Author.objects.create(name='Margaret Smith')>>> author = Author.objects.annotate(... name_length=Length('name'),... goes_by_length=Length('goes_by')).get()>>> print(author.name_length, author.goes_by_length)(14, None) |
It can also be registered as a transform. For example:
1 2 3 4 5 | >>> from django.db.models import CharField>>> from django.db.models.functions import Length>>> CharField.register_lookup(Length, 'length')>>> # Get authors whose name is longer than 7 characters>>> authors = Author.objects.filter(name__length__gt=7) |
Changed in Django 1.9:
The ability to register the function as a transform was added.
Please login to continue.