Django DRF - Group by date - django

Question

I need to group the result of a queryset by date on DRF
""" Django model """
class Matches(models.Model):
name = models.CharField(max_length=100)
platform = models.CharField(max_length=100)
mode = models.CharField(max_length=100)
kills = models.IntegerField()
date = models.DateTimeField()
""" Serializer """
class MatchesSerializer(serializers.ModelSerializer):
class Meta:
model = models.Matches
fields = ('name', 'platform', 'mode', 'kills', 'date')
""" views """
class Matches(generics.ListAPIView):
serializer_class = serializers.MatchesSerializer
filter_backends = (filters.OrderingFilter,)
lookup_field = 'name'
ordering = ('-date',)
def get_queryset(self):
username = self.kwargs['name']
return models.Matches.objects.filter(name=username)
Desired output (just an example):
[
{
'date':'2019-01-01',
'data':[
{
'platform':'ps4',
'mode':'solo',
'kills':10,
'date':'2019-01-01 10:00:00'
},
{
'platform':'ps4',
'mode':'duo',
'kills':10,
'date':'2019-01-01 12:00:00'
},
{
'platform':'ps4',
'mode':'squad',
'kills':10,
'date':'2019-01-01 11:00:00'
},
]
},
{
'date':'2019-01-02',
'data':[
{
'platform':'ps4',
'mode':'solo',
'kills':1,
'date':'2019-01-02 10:00:00'
},
{
'platform':'ps4',
'mode':'duo',
'kills':2,
'date':'2019-01-02 12:00:00'
},
{
'platform':'ps4',
'mode':'squad',
'kills':3,
'date':'2019-01-02 11:00:00'
},
]
}
]
For me, the easy solution is to make a raw querie on django and create a serializer, but it feels not so pythonic...
So it appears that DRF has some beautiful way to make it look nice, maybe using to_representation...

Answer 1

I used the itertools.groupby iterator. Check my code below.
from itertools import groupby
events = [["2020-04-01", "A"], ["2020-04-01", "B"], ["2020-04-02", "C"], ["2020-04-02", "D"]]
for k, g in groupby(events, lambda x: x[0]):
list = []
for group in g:
list.append(group[1])
output[k] = list
The output will be grouped by date as follows
{'2020-04-01': ['A', 'B'], '2020-04-02': ['C', 'D']}
Please make sure your order by date first.

Answer 2

You can use the function raw from Django ORM
results = Matches.objects.raw('SELECT * FROM myapp_matches GROUP BY date')