Aggregation

qalx provides an interface to the MongoDB aggregation pipeline. This powerful feature allows you to perform many complex operations on your data using the aggregate argument.

Grouping some items.

>>> from pyqalx import QalxSession
>>> qalx = QalxSession()

>>> # First, let's add some items to perform the aggregation on
>>> items = [{"data": {"key": "aggregation_example",
>>>                    "value": x % 2}} for x in range(0, 15)]
>>> qalx.item.add_many(items=items)

>>> # This simple aggregation groups data on the `value` key after filtering
>>> # the data on a specific key
>>> qalx.item.aggregate(aggregate=[
>>>                         {"$match": {"data.key": "aggregation_example"}},
>>>                         {"$group": {"_id": "$data.value", "count": {"$sum": 1}}}])
{'aggregate': [{'$match': {'data.key': 'aggregation_example'}},
               {'$group': {'_id': '$data.value', 'count': {'$sum': 1}}}]},
 'data': [{'_id': 1, 'count': 7}, {'_id': 0, 'count': 8}]}

Consult the MongoDB documentation for more information about what is possible using aggregation