Django rest API: How I can serialize data properly - django

Question

I am new to django rest framework. I am getting the response data for not in the format I need. Any help will be appreciated. Below is my code.
model.py
class Price(models.Model):
ticker = models.CharField(max_length=15, null=False, blank=False)
price_date=models.DateField(null=False, blank=False)
daily_pe = models.FloatField(blank=True, null=True)
class Meta:
db_table= 'price'
unique_together = ('ticker', 'price_date')
def __str__(self):
return "%s %s %s " % (self.ticker, self.price_date, daily_pe)
serializers.py
class ChartSerilizer(serializers.ModelSerializer):
class Meta:
model = Price
fields = ['ticker', 'daily_pe']
view.py
class peChartViewSet(APIView):
def get(self, request):
queryset = Price.objects.all()
serializer = ChartSerilizer(queryset, many=True)
return JsonResponse(serializer.data, safe=False)
This is how am getting the response:
[
{
"ticker": "AAPL",
"daily_pe": 25.144920802584345
},
{
"ticker": "AAPL",
"daily_pe": 25.043920960028977
},
{
"ticker": "WMT",
"daily_pe": 24.930801136366966
},
{
"ticker": "WMT",
"daily_pe": 25.504480242081453
},
]
But I need the response like this :
[
{
"Ticker": "AAPL",
"daily_pe": [25.144920802584345, 25.043920960028977]
},
{
"Ticker": "WMT",
"daily_pe": [24.930801136366966,25.504480242081453]
}
]

Answer 1

you can do the thing you wanted by using ArrayAgg aggregation function
views.py
from django.contrib.postgres.aggregates import ArrayAgg
class peChartViewSet(APIView):
def get(self, request):
queryset = Price.objects.values('ticker').annotate(
daily_pe_list=ArrayAgg('daily_pe')
)
serializer = ChartSerilizer(queryset, many=True)
return JsonResponse(serializer.data, safe=False)
and also change daily_pe's type to ListField
serializers.py
class ChartSerilizer(serializers.ModelSerializer):
Ticker = serializers.CharField(source='ticker')
daily_pe = serializers.ListField(source='daily_pe_list')
class Meta:
model = Price
fields = ['Ticker', 'daily_pe']
based on your answer, you want result list in order of price_date, so for this purpose, you can add ordering argument to ArrayAgg like this:
queryset = Price.objects.values('ticker').annotate(
daily_pe_list=ArrayAgg('daily_pe', ordering='price_date')
)
* sorry I answered late, i wasn't around my pc.

Answer 2

There must me a better way, but I got desired result (almost).
Here is my updated view.py
class peChartViewSet(APIView):
def get(self, request):
tickers = ['AAPL', 'WMT']
data=[]
for tick in tickers:
print(tick)
# tick = request.query_params["ticker"]
queryset = Price.objects.all().filter(ticker=tick).order_by('price_date')
serializer = ChartSerilizer(queryset, many=True)
data.append({tick : serializer.data})
return Response(data)