def std(self, sample=False):
"""
Standard deviation of value.
If sample=True, return the sample standard deviation.
"""
return models.StdDev(self._name, sample=sample)
def test_functions(self):
aggregations = [
Aggregation("population", "population_max", models.Max),
Aggregation("population", "population_min", models.Min),
Aggregation("population", "population_avg", models.Avg),
Aggregation("population", "population_sum", models.Sum),
Aggregation("population", "population_cnt", models.Count),
]
expected = Country.objects.all().aggregate(
population_max=models.Max("population"), population_min=models.Min("population"),
population_avg=models.Avg("population"), population_sum=models.Sum("population"),
population_cnt=models.Count("population"),
)
if version.parse(".".join(map(str, django.VERSION))) >= version.parse("2.2.0"):
aggregations.append(Aggregation("population", "population_stddev", models.StdDev))
aggregations.append(Aggregation("population", "population_var", models.Variance), )
expected = expected.aggregate(
population_stddev=models.StdDev("population"),
population_var=models.Variance("population")
)
aggregations = [a.get() for a in aggregations]
kwargs = dict(aggregations)
query = Country.objects.all().aggregate(**kwargs)
self.assertEqual(expected, query)
def generate(self):
super().generate()
assessment_set = self.snapshot_assessment_set()
self.candidate_ratings = {
result['student_id']: result['rating']
for result in assessment_set.values('student_id', 'rating')
}
self.rating_average = assessment_set.aggregate(
rating_average=models.Avg('rating'))['rating_average'] or 0
self.rating_std_dev = assessment_set.aggregate(
rating_std_dev=models.StdDev('rating'))['rating_std_dev'] or 0
return self
def stats(self, request, *args, **kwargs):
"""
stats on rates
"""
period = request.GET.get('period', 'month')
if period not in ['week', 'month', 'year']:
return Response("Invalid period",
status=status.HTTP_400_BAD_REQUEST)
rate_filter = RateFilter(request.GET,
queryset=self.queryset,
request=request)
qs = rate_filter.qs.values('currency', 'base_currency')
if period == 'month':
qs = qs.annotate(month=Extract('value_date', 'month'))
if period == 'week':
qs = qs.annotate(week=Extract('value_date', 'week'))
qs = qs.annotate(year=Extract('value_date', 'year'),
avg=models.Avg('value'),
max=models.Max('value'),
min=models.Min('value'),
std_dev=models.StdDev('value')).order_by(
'-year', '-' + period)
results = [{
'currency':
result['currency'],
'base_currency':
result['base_currency'],
'period':
f"{result['year']}-{str(result[period]).zfill(2)}"
if period != 'year' else result['year'],
'avg':
result['avg'],
'max':
result['max'],
'min':
result['min'],
'std_dev':
result['std_dev'],
} for result in qs]
data = {
'key': request.GET.get('key'),
'period': period,
'from_date': request.GET.get('from_date', ''),
'to_date': request.GET.get('to_date', ''),
'results': results
}
serializer = RateStatSerializer(data)
return Response(serializer.data, content_type="application/json")
def stddev(self):
return self.row_set.all().aggregate(
stddev=models.StdDev('value'))['stddev']