django - 如何通过 Django 中的模型属性之一对对象数组进行分组?
问题描述
我想做类似于这个例子的事情如何按键分组对象数组,但我在 Django 中找不到 API Get 的解决方案。
这是我所拥有的一个例子:
[
{
"id": 1,
"nutrition_measurement_id": "1",
"nutrition_type_id": "2",
"feeding_time": "dinner"
},
{
"id": 2,
"nutrition_measurement_id": "2",
"nutrition_type_id": "1",
"feeding_time": "dinner"
},
{
"id": 3,
"nutrition_measurement_id": "3",
"nutrition_type_id": "2",
"feeding_time": "breakfast"
},
{
"id": 4,
"nutrition_measurement_id": "2",
"nutrition_type_id": "1",
"feeding_time": "breakfast"
}
]
这是我想要实现的示例:
{
"dinner": [
{
"id": 3,
"nutrition_type_id": 2,
"nutrition_measurement_id": 1
},
{
"id": 3,
"nutrition_type_id": 1,
"nutrition_measurement_id": 2
}
],
"breakfast": [
{
"id": 3,
"nutrition_type_id": 2,
"nutrition_measurement_id": 3
},
{
"id": 5,
"nutrition_type_id": 1,
"nutrition_measurement_id": 4
}
]
}
以下是我拥有的模型:
class HorseNutrition(models.Model):
horse = models.ForeignKey(Horse, models.DO_NOTHING)
nutrition_type = models.ForeignKey('NutritionType', models.DO_NOTHING)
nutrition_measurement = models.ForeignKey('NutritionMeasurement', models.DO_NOTHING)
feeding_time = models.CharField(max_length=10, blank=True, null=True)
class Meta:
managed = False
db_table = 'horse_nutrition'
class NutritionMeasurement(models.Model):
name = models.CharField(unique=True, max_length=30, blank=True, null=True)
class Meta:
managed = False
db_table = 'nutrition_measurement'
def __str__(self):
return self.name
def __unicode__(self):
return self.name
class NutritionType(models.Model):
name = models.CharField(unique=True, max_length=30, blank=True, null=True)
class Meta:
managed = False
db_table = 'nutrition_type'
def __str__(self):
return self.name
def __unicode__(self):
return self.name
这是我的序列化程序
class HorseNutritionSerializer(serializers.ModelSerializer):
nutrition_measurement_id = serializers.ReadOnlyField(source = 'nutrition_measurement.name')
nutrition_type_id = serializers.ReadOnlyField(source = 'nutrition_type.name')
class Meta:
model = HorseNutrition
fields = ['id', 'nutrition_measurement_id', 'nutrition_type_id', 'feeding_time']
这是我的看法:
class HorseNutritionView(APIView):
def get (self, request, format = None):
#id = int(request.GET.get(self.lookup_url_kwarg))
id = 1
if id != None:
queryset = HorseNutrition.objects.filter(horse_id = id)
serializer = HorseNutritionSerializer(queryset, many = True)
return Response(serializer.data)
else:
return Response(status = status.HTTP_400_BAD_REQUEST)
解决方案
您可以使用自定义ListSerializer
(我们将list_serializer_class
在Meta
您的序列化程序中设置)并覆盖它to_representation
并用于itertools.groupby
对您的结果进行分组:
from itertools import groupby
class HorseNutritionListSerializer(serializers.ListSerializer):
def to_representation(self, data):
ret = super().to_representation(data)
return {key: list(group) for key, group in groupby(ret, key=lambda x: x['feeding_time'])}
@property
def data(self):
ret = serializers.BaseSerializer.data.fget(self)
return serializers.ReturnDict(ret, serializer=self)
class HorseNutritionSerializer(serializers.ModelSerializer):
nutrition_measurement_id = serializers.ReadOnlyField(source = 'nutrition_measurement.name')
nutrition_type_id = serializers.ReadOnlyField(source = 'nutrition_type.name')
class Meta:
model = HorseNutrition
fields = ['id', 'nutrition_measurement_id', 'nutrition_type_id', 'feeding_time']
list_serializer_class = HorseNutritionListSerializer
此外,要正确完成此分组,您的查询集必须排序,您可以在视图中执行此操作:
class HorseNutritionView(APIView):
def get (self, request, format = None):
#id = int(request.GET.get(self.lookup_url_kwarg))
id = 1
if id != None:
queryset = HorseNutrition.objects.filter(horse_id = id).order_by('feeding_time')
serializer = HorseNutritionSerializer(queryset, many = True)
return Response(serializer.data)
else:
return Response(status = status.HTTP_400_BAD_REQUEST)
推荐阅读
- python - 在非协程方法中调度协程
- react-native - Agora.io 视频流切割纵向和横向视频
- python - Pandas groupby 和 diff 基于两列
- azure - Azure(kubernetes 集群)中的监控网络节流限制?
- regex - sed 正则表达式不考虑双引号或空格
- authentication - Nuxt Apollo 模块请求授权标头,带有双 'Bearer'
- javascript - 如何将回调函数变成 Promise
- .htaccess - RewriteCond %{REMOTE_ADDR} [IPv4] 阻止捕获 IP 范围?
- php - 当它包含php代码时如何在点击时传递一个img src值
- c# - 如何将 DateTimePicker 下拉菜单设置为仅选择年或月?