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Merge pull request #1021 from elasticsales/aggregate-sum-and-avg

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aggregate_sum/average + unit tests
This commit is contained in:
Matthieu Rigal 2015-06-18 23:14:27 +02:00
commit 5fa5284b58
3 changed files with 105 additions and 6 deletions
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1
docs/changelog.rst
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@ -25,6 +25,7 @@ Changes in 0.9.X - DEV
- Updated URL and Email Field regex validators, added schemes argument to URLField validation. #652
- Removed get_or_create() deprecated since 0.8.0. #300
- Capped collection multiple of 256. #1011
- Added `BaseQuerySet.aggregate_sum` and `BaseQuerySet.aggregate_average` methods.
Changes in 0.9.0
================

42
mongoengine/queryset/base.py
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@ -1248,6 +1248,27 @@ class BaseQuerySet(object):
else:
return 0
def aggregate_sum(self, field):
"""Sum over the values of the specified field.
:param field: the field to sum over; use dot-notation to refer to
embedded document fields
This method is more performant than the regular `sum`, because it uses
the aggregation framework instead of map-reduce.
"""
result = self._document._get_collection().aggregate([
{ '$match': self._query },
{ '$group': { '_id': 'sum', 'total': { '$sum': '$' + field } } }
])
if IS_PYMONGO_3:
result = list(result)
else:
result = result.get('result')
if result:
return result[0]['total']
return 0
def average(self, field):
"""Average over the values of the specified field.
@ -1303,6 +1324,27 @@ class BaseQuerySet(object):
else:
return 0
def aggregate_average(self, field):
"""Average over the values of the specified field.
:param field: the field to average over; use dot-notation to refer to
embedded document fields
This method is more performant than the regular `average`, because it
uses the aggregation framework instead of map-reduce.
"""
result = self._document._get_collection().aggregate([
{ '$match': self._query },
{ '$group': { '_id': 'avg', 'total': { '$avg': '$' + field } } }
])
if IS_PYMONGO_3:
result = list(result)
else:
result = result.get('result')
if result:
return result[0]['total']
return 0
def item_frequencies(self, field, normalize=False, map_reduce=True):
"""Returns a dictionary of all items present in a field across
the whole queried set of documents, and their corresponding frequency.

68
tests/queryset/queryset.py
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@ -2706,26 +2706,58 @@ class QuerySetTest(unittest.TestCase):
avg = float(sum(ages)) / (len(ages) + 1) # take into account the 0
self.assertAlmostEqual(int(self.Person.objects.average('age')), avg)
self.assertAlmostEqual(
int(self.Person.objects.aggregate_average('age')), avg
)
self.Person(name='ageless person').save()
self.assertEqual(int(self.Person.objects.average('age')), avg)
self.assertEqual(
int(self.Person.objects.aggregate_average('age')), avg
)
# dot notation
self.Person(
name='person meta', person_meta=self.PersonMeta(weight=0)).save()
self.assertAlmostEqual(
int(self.Person.objects.average('person_meta.weight')), 0)
self.assertAlmostEqual(
int(self.Person.objects.aggregate_average('person_meta.weight')),
0
)
for i, weight in enumerate(ages):
self.Person(
name='test meta%i', person_meta=self.PersonMeta(weight=weight)).save()
self.assertAlmostEqual(
int(self.Person.objects.average('person_meta.weight')), avg)
int(self.Person.objects.average('person_meta.weight')), avg
)
self.assertAlmostEqual(
int(self.Person.objects.aggregate_average('person_meta.weight')),
avg
)
self.Person(name='test meta none').save()
self.assertEqual(
int(self.Person.objects.average('person_meta.weight')), avg)
int(self.Person.objects.average('person_meta.weight')), avg
)
self.assertEqual(
int(self.Person.objects.aggregate_average('person_meta.weight')),
avg
)
# test summing over a filtered queryset
over_50 = [a for a in ages if a >= 50]
avg = float(sum(over_50)) / len(over_50)
self.assertEqual(
self.Person.objects.filter(age__gte=50).average('age'),
avg
)
self.assertEqual(
self.Person.objects.filter(age__gte=50).aggregate_average('age'),
avg
)
def test_sum(self):
"""Ensure that field can be summed over correctly.
@ -2734,20 +2766,44 @@ class QuerySetTest(unittest.TestCase):
for i, age in enumerate(ages):
self.Person(name='test%s' % i, age=age).save()
self.assertEqual(int(self.Person.objects.sum('age')), sum(ages))
self.assertEqual(self.Person.objects.sum('age'), sum(ages))
self.assertEqual(
self.Person.objects.aggregate_sum('age'), sum(ages)
)
self.Person(name='ageless person').save()
self.assertEqual(int(self.Person.objects.sum('age')), sum(ages))
self.assertEqual(self.Person.objects.sum('age'), sum(ages))
self.assertEqual(
self.Person.objects.aggregate_sum('age'), sum(ages)
)
for i, age in enumerate(ages):
self.Person(name='test meta%s' %
i, person_meta=self.PersonMeta(weight=age)).save()
self.assertEqual(
int(self.Person.objects.sum('person_meta.weight')), sum(ages))
self.Person.objects.sum('person_meta.weight'), sum(ages)
)
self.assertEqual(
self.Person.objects.aggregate_sum('person_meta.weight'),
sum(ages)
)
self.Person(name='weightless person').save()
self.assertEqual(int(self.Person.objects.sum('age')), sum(ages))
self.assertEqual(self.Person.objects.sum('age'), sum(ages))
self.assertEqual(
self.Person.objects.aggregate_sum('age'), sum(ages)
)
# test summing over a filtered queryset
self.assertEqual(
self.Person.objects.filter(age__gte=50).sum('age'),
sum([a for a in ages if a >= 50])
)
self.assertEqual(
self.Person.objects.filter(age__gte=50).aggregate_sum('age'),
sum([a for a in ages if a >= 50])
)
def test_embedded_average(self):
class Pay(EmbeddedDocument):