How many time can django objects.filter Q() be used in one query?

Question

Given my user table has a big list of users which name can start with number or letter, how can I get users that name starts with A to Z?

I tried the following but it didn't work.

users = User.objects.filter(reduce(operator.or_, [Q(name__startswith=letter) for letter in 'ABCDEFGHIJKLMNOPQRSTUVWXYZ']))

However, if I tried the following, it worked

users = User.objects.filter(reduce(operator.or_, [Q(name__startswith=letter) for letter in 'ABCDEFGHI']))

It seems like the Q() is limited to 9 times in objects.filter. Could you please advise? Thanks!

Answer 1

Why don't you use the Regex filter?

users = User.objects.filter(name__iregex=r'^[A-Z]')
for user in users:
    print user.name

Here is how I just tried in my local test django project: Just created a Model as:

from django.db import models

class Users(models.Model):
    name = models.CharField(max_length=50)

Ran a django manage.py shell command, imported this model, and created, 3 users:

>>>Users.objects.create(name="FirstUser").save()
>>>Users.objects.create(name="SecondUser").save()
>>>Users.objects.create(name="12NumberedUser").save()

>>> for i in Users.objects.filter(name__iregex=r'^[A-Z]'):
...     print i.name
...
FirstUser
SecondUser
>>>

Also, for Q its the same way, but there is no need of Q if you have got only one condition.

Hope that helps.