Django ManyToMany过滤器（） [英] Django ManyToMany filter()

问题描述

我有一个模型：

class Zone(models.Model):
    name = models.CharField(max_length=128)
    users = models.ManyToManyField(User, related_name='zones', null=True, blank=True)

我需要按照以下方式构造一个过滤器：

And I need to contruct a filter along the lines of:

u = User.objects.filter(...zones contains a particular zone...)

它必须是一个过滤器在用户上，它必须是单个过滤器参数。原因是我正在构建一个URL查询字符串来过滤管理员用户更改列表： http：// myserver / admin / auth / user /？zones = 3

It has to be a filter on User and it has to be a single filter parameter. The reason for this is that I am constructing a URL querystring to filter the admin user changelist: http://myserver/admin/auth/user/?zones=3

看起来应该很简单，但我的大脑不合作！

It seems like it should be simple but my brain isn't cooperating!

推荐答案

有很多例子是 FOO__in = ... 样式过滤器 many-to-many and 多对一测试。以下是您的特定问题的语法：

There are many examples of FOO__in=... style filters in the many-to-many and many-to-one tests. Here is syntax for your specific problem:

users_in_1zone = User.objects.filter(zones__id=<id1>)
# same thing but using in
users_in_1zone = User.objects.filter(zones__in=[<id1>])

# filtering on a few zones, by id
users_in_zones = User.objects.filter(zones__in=[<id1>, <id2>, <id3>])
# and by zone object (object gets converted to pk under the covers)
users_in_zones = User.objects.filter(zones__in=[zone1, zone2, zone3])

双下划线使用查询结果时，会使用__）语法。

The double underscore (__) syntax is used all over the place when working with querysets.

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