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ASF GitHub Bot commented on FLINK-3650: --------------------------------------- Github user ramkrish86 commented on a diff in the pull request: https://github.com/apache/flink/pull/1856#discussion_r61918711 --- Diff: flink-scala/src/main/scala/org/apache/flink/api/scala/DataSet.scala --- @@ -1599,7 +1601,77 @@ class DataSet[T: ClassTag](set: JavaDataSet[T]) { def output(outputFormat: OutputFormat[T]): DataSink[T] = { javaSet.output(outputFormat) } - + + /** + * Selects an element with minimum value. + * <p> + * The minimum is computed over the specified fields in lexicographical order. + * <p> + * <strong>Example 1</strong>: Given a data set with elements <code>[0, 1], [1, 0]</code>, the + * results will be: + * <ul> + * <li><code>minBy(0)</code>: <code>[0, 1]</code></li> + * <li><code>minBy(1)</code>: <code>[1, 0]</code></li> + * </ul> + * <p> + * <strong>Example 2</strong>: Given a data set with elements <code>[0, 0], [0, 1]</code>, the + * results will be: + * <ul> + * <li><code>minBy(0, 1)</code>: <code>[0, 0]</code></li> + * </ul> + * <p> + * If multiple values with minimum value at the specified fields exist, a random one will be + * picked. + * <p> + * Internally, this operation is implemented as a {@link ReduceFunction}. + * + */ + def minBy(fields: Int*) : Unit = { --- End diff -- This should return the ReduceOperator. My bad. Not sure whether the existing test case really tests the entire functionality. > Add maxBy/minBy to Scala DataSet API > ------------------------------------ > > Key: FLINK-3650 > URL: https://issues.apache.org/jira/browse/FLINK-3650 > Project: Flink > Issue Type: Improvement > Components: Java API, Scala API > Affects Versions: 1.1.0 > Reporter: Till Rohrmann > Assignee: ramkrishna.s.vasudevan > > The stable Java DataSet API contains the API calls {{maxBy}} and {{minBy}}. > These methods are not supported by the Scala DataSet API. These methods > should be added in order to have a consistent API. -- This message was sent by Atlassian JIRA (v6.3.4#6332)