How to make it by list comprehension - django-models

Question

I need to get the child list under the parent list as a group.
class ServiceSerializer(serializers.ModelSerializer):
cleaning_type = serializers.CharField(source='cleaning_type.cleaning_type_name')
class Meta:
model = Service
fields = ('id', 'cleaning_type','service_name')
class ServiceTypeViewSet(ModelViewSet):
serializer_class = ServiceSerializer
http_method_names = ["get"]
queryset = Service.objects.all()
def get_queryset(self):
"""
This view should return a list of all the service types.
"""
servicename_list = Service.objects.all()
return servicename_list
It shows:
[
{
"id": 1,
"cleaning_type": "Lite service",
"service_name": "Floors",
},
{
"id": 2,
"cleaning_type": "Lite service",
"service_name": "Bathrooms",
},
{
"id": 3,
"cleaning_type": "Lite service",
"service_name": "Kitchen",
}
]
I want this to be in the following format:
[
{
id: 1,
cleaning_type: 'Lite service',
service_name: ['Floors', 'bathroom', 'kitchen'],
},
{
id: 2,
cleaning_type: 'Moving cleaning',
service_name: ['Kitchen Including All Appliances And Cabinets'],
},
]
That means all child elements will be under a separate parent list. Not separate by separate.
models.py is here:
Cleaning Type Model:
class CleaningType(models.Model):
cleaning_type_name = models.CharField(
_("Select Cleaning Type"), blank=True, null=True, max_length=255)
price = models.DecimalField(default=0,max_digits=6, decimal_places=2)
def __str__(self):
return self.cleaning_type_name
Service Model:
class Service(models.Model):
cleaning_type = models.ForeignKey(
CleaningType, on_delete=models.CASCADE)
service_name = models.CharField(
_("Service Name"), blank=True, null=True, max_length=255)
#string type added
def __str__(self):
return str(self.service_name)
I want sub categories under parent caterories. Here cleaning_type is the parent category and service is the child category of cleaning_type. i.e : cleaning_type >> service_type

Answer 1

First you need to move the cleaningtype field into the ServiceType model.
And I think it's better to set the related_name from the view of the target model.
class ServiceType(models.Model):
cleaningtype = models.ForeignKey(
CleaningType, related_name='service_types', on_delete=models.CASCADE)
...
class Service(models.Model):
servicetype = models.ForeignKey(
ServiceType, related_name='services', on_delete=models.CASCADE)
service_name = models.CharField(
_("Service Name"), blank=True, null=True, max_length=255)
#string type added
def __str__(self):
return str(self.service_name)
And in CleaningTypeSerializer
class CleaningTypeSerializer(serializers.ModelSerializer):
service_objects = ServiceTypeSerializer(many = True, read_only = True)
service_types = serializers.SerializerMethodField()
class Meta:
Model = CleaningType
fields = ('id', 'cleaning_type', 'service_types',)
def get_service_types(self, obj):
return list(obj.service_types.values_list('service_type').distinct())
Finally in views.py,
class CleaningTypesViewSet(ModelViewSet):
serializer_class = CleaningTypeSerializer
queryset = CleaningType.objects.all()
You can get the list of CleaningType data from this CleaningTypesViewSet.