Github user zentol commented on a diff in the pull request:
https://github.com/apache/flink/pull/2115#discussion_r67940988
--- Diff:
flink-libraries/flink-python/src/main/python/org/apache/flink/python/api/flink/plan/DataSet.py
---
@@ -192,6 +193,30 @@ def reduce(self, operator):
self._env._sets.append(child)
return child_set
+ def aggregate(self, aggregation, field):
+ """
+ Applies an Aggregate transformation (using a GroupReduceFunction)
on a non-grouped Tuple DataSet.
+ :param aggregation: The built-in aggregation function to apply on
the DataSet.
+ :param field: The index of the Tuple field on which to perform the
function.
+ :return: A GroupReduceOperator that represents the aggregated
DataSet.
+ """
+ child_set = self.reduce_group(aggregation(field), combinable=True)
+ child_set._info.name = "PythonAggregate"
+ return child_set
+
+ def agg_and(self, aggregation, field):
+ """
+ Applies an additional Aggregate transformation.
+ :param aggregation: The built-in aggregation operation to apply on
the DataSet.
+ :param field: The index of the Tuple field on which to perform the
function.
+ :return: A GroupReduceOperator that represents the aggregated
DataSet.
+ """
+ if self._info.name == "PythonAggregate":
--- End diff --
this is a bit icky. it would be better to create a separate
AggregateOperator class that inherits from DataSet and contains the agg_and
method. (similar to how cross/join works)
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