How do I make a query where it filters everything that starts with a number in Django?

Question

I have a model called Book with a Title Field.

class Book(models.Model):
    title = models.CharField(null = False,blank=False)

Now I need a filter to get all books with titles starting with a number.

This works but how will I extend the queryset?

b = Book.objects.filter(title__startswith = 1).order_by('title')

This doesn't work

b = b + Book.objects.filter(title__startswith = 2).order_by('title')

or this

b.extend(Book.objects.filter(title__startswith = 2).order_by('title'))

Answer 1

You can use a regular expression as a query parameter to check that the a value starts with a number:

Book.objects.filter(title__regex=r'^\d')