Method average

mongoengine/queryset/base.py:1590–1614

Average over the values of the specified field. :param field: the field to average over; use dot notation to refer to embedded document fields

(self, field)

        return 0

    def 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
        """
        db_field = self._fields_to_dbfields([field]).pop()
        pipeline = [
            {"$match": self._query},
            {"$group": {"_id": "avg", "total": {"$avg": "$" + db_field}}},
        ]

        # if we're performing an average over a list field, we average out
        # all the elements in the list, hence we need to $unwind the arrays
        # first
        ListField = _import_class("ListField")
        field_parts = field.split(".")
        field_instances = self._document._lookup_field(field_parts)
        if isinstance(field_instances[-1], ListField):
            pipeline.insert(1, {"$unwind": "$" + field})

        result = tuple(self._document._get_collection().aggregate(pipeline))
        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