Python django在序列化时从模型实例筛选一个对象

我有一个带有m2m字段的django模型，我想定制序列化程序，以便只过滤所需的数据。代码如下所示

models.py

：

class Example(models.Model):
    field = models.CharField(max_length=25)
    users = models.ManyToManyField(User)

class UserSerializer(serializers.ModelSerializer):
    def to_representation(self, instance):
        return {"""... processing User's fields..."""}

class ExampleSerializer(serializers.ModelSerialzier):
    def to_representation(self, instance):
        user = self.context
        result = {... some fields ...}
        if instance.field == "some_value":
            ### IN THIS CASE THERE ARE ONLY TWO USERS, NEVER MORE###
            result['users'] = UserSerializer(instance.users.exclude(id=user.id)[0]).data
        else:
            result['users'] = ...

ExampleSerializer(Example.objects.all(), many=True, context=user).data

serializers.py

：

class Example(models.Model):
    field = models.CharField(max_length=25)
    users = models.ManyToManyField(User)

class UserSerializer(serializers.ModelSerializer):
    def to_representation(self, instance):
        return {"""... processing User's fields..."""}

class ExampleSerializer(serializers.ModelSerialzier):
    def to_representation(self, instance):
        user = self.context
        result = {... some fields ...}
        if instance.field == "some_value":
            ### IN THIS CASE THERE ARE ONLY TWO USERS, NEVER MORE###
            result['users'] = UserSerializer(instance.users.exclude(id=user.id)[0]).data
        else:
            result['users'] = ...

ExampleSerializer(Example.objects.all(), many=True, context=user).data

views.py

：

class Example(models.Model):
    field = models.CharField(max_length=25)
    users = models.ManyToManyField(User)

class UserSerializer(serializers.ModelSerializer):
    def to_representation(self, instance):
        return {"""... processing User's fields..."""}

class ExampleSerializer(serializers.ModelSerialzier):
    def to_representation(self, instance):
        user = self.context
        result = {... some fields ...}
        if instance.field == "some_value":
            ### IN THIS CASE THERE ARE ONLY TWO USERS, NEVER MORE###
            result['users'] = UserSerializer(instance.users.exclude(id=user.id)[0]).data
        else:
            result['users'] = ...

ExampleSerializer(Example.objects.all(), many=True, context=user).data

我不确定你还需要什么，但请随便问

所以问题是，如果

type

是“some_value”，我只想得到一个不是发起此调用的用户，它工作正常，但看起来很难看，而且我不确定在高负载下执行是否足够快。当然，我可以为这种情况编写另一个自定义序列化程序，但仍在寻找最佳解决方案

python中有内置选项吗

我注意到，对于这样的操作，序列化程序并不是很快，有什么方法可以节省时间吗？像索引之类的东西

---

提前感谢您的回复

type

是python内置的。它不应该是

“some value”

@HåkenLid type是自定义名称字段，在我的模型中名称不同，但感谢您的评论