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https://issues.apache.org/jira/browse/FLINK-2184?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15573299#comment-15573299
]
ASF GitHub Bot commented on FLINK-2184:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/1975#discussion_r83318300
--- Diff:
flink-streaming-scala/src/main/scala/org/apache/flink/streaming/api/scala/KeyedStream.scala
---
@@ -224,45 +224,95 @@ class KeyedStream[T, K](javaStream:
KeyedJavaStream[T, K]) extends DataStream[T]
/**
* Applies an aggregation that that gives the current minimum element of
the data stream by
* the given position by the given key. An independent aggregate is kept
per key.
- * When equality, the first element is returned with the minimal value.
+ * When equality, the first element is returned with the minimal value
by default.
*
*/
def minBy(position: Int): DataStream[T] = aggregate(AggregationType
- .MINBY, position)
-
- /**
+ .MINBY, position, true)
+
+ /**
* Applies an aggregation that that gives the current minimum element of
the data stream by
- * the given field by the given key. An independent aggregate is kept
per key.
- * When equality, the first element is returned with the minimal value.
+ * the given position by the given key. An independent aggregate is kept
per key.
+ * When equality, returns either the first or last one depending on the
parameter setting.
+ *
+ */
+ def minBy(position: Int, first: Boolean): DataStream[T] =
aggregate(AggregationType
+ .MINBY, position, first)
+
+ /**
+ * Applies an aggregation that that gives the current minimum element of
the data stream by
+ * the given field by the given key. An independent aggregate is kept
per key.
+ * When equality, the first element is returned with the minimal value
by default.
*
*/
def minBy(field: String): DataStream[T] = aggregate(AggregationType
- .MINBY, field )
+ .MINBY, field, true)
+
+ /**
+ * Applies an aggregation that that gives the current minimum element of
the data stream by
+ * the given field by the given key. An independent aggregate is kept
per key.
+ * When equality, returns either the first or last one depending on the
parameter setting.
+ *
+ */
+ def minBy(field: String, first: Boolean): DataStream[T] =
aggregate(AggregationType
+ .MINBY, field, first)
/**
* Applies an aggregation that that gives the current maximum element of
the data stream by
* the given position by the given key. An independent aggregate is kept
per key.
- * When equality, the first element is returned with the maximal value.
+ * When equality, the first element is returned with the maximal value
by default.
*
*/
def maxBy(position: Int): DataStream[T] =
- aggregate(AggregationType.MAXBY, position)
-
- /**
+ aggregate(AggregationType.MAXBY, position, true)
+
+ /**
+ * Applies an aggregation that that gives the current maximum element of
the data stream by
+ * the given position by the given key. An independent aggregate is kept
per key.
+ * When equality, returns either the first or last one depending on the
parameter setting.
+ *
+ */
+ def maxBy(position: Int, first: Boolean): DataStream[T] =
+ aggregate(AggregationType.MAXBY, position, first)
+
+ /**
* Applies an aggregation that that gives the current maximum element of
the data stream by
* the given field by the given key. An independent aggregate is kept
per key.
- * When equality, the first element is returned with the maximal value.
+ * When equality, the first element is returned with the maximal value
by default.
*
*/
def maxBy(field: String): DataStream[T] =
- aggregate(AggregationType.MAXBY, field)
-
+ aggregate(AggregationType.MAXBY, field, true)
+
+ /**
+ * Applies an aggregation that that gives the current maximum element of
the data stream by
+ * the given field by the given key. An independent aggregate is kept
per key.
+ * When equality, returns either the first or last one depending on the
parameter setting.
+ *
+ */
+ def maxBy(field: String, first: Boolean): DataStream[T] =
+ aggregate(AggregationType.MAXBY, field, first)
+
+ private def aggregate(aggregationType: AggregationType, position: Int):
DataStream[T] = {
+ aggregate(aggregationType, position, false)
--- End diff --
default should be `true` instead of `false`
> Cannot get last element with maxBy/minBy
> ----------------------------------------
>
> Key: FLINK-2184
> URL: https://issues.apache.org/jira/browse/FLINK-2184
> Project: Flink
> Issue Type: Improvement
> Components: Scala API, Streaming
> Reporter: Gábor Hermann
> Priority: Minor
>
> In the streaming Scala API there is no method
> {{maxBy(int positionToMaxBy, boolean first)}}
> nor
> {{minBy(int positionToMinBy, boolean first)}}
> like in the Java API, where _first_ set to {{true}} indicates that the latest
> found element will return.
> These methods should be added to the Scala API too, in order to be consistent.
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