[SPARK-15807] Support varargs for dropDuplicates in Dataset/DataFrame

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Component/s: SQL
• Assignee: Dongjoon Hyun
• Reporter: Dongjoon Hyun
• Created: 07/Jun/16 18:33
• Updated: 13/Jun/16 02:13
• Resolved: 11/Jun/16 22:47

Description

This issue adds `varargs`-types `dropDuplicates` functions in `Dataset/DataFrame`. Currently, `dropDuplicates` supports only `Seq` or `Array`.

scala> val ds = spark.createDataFrame(Seq(("a", 1), ("b", 2), ("a", 2)))
ds: org.apache.spark.sql.DataFrame = [_1: string, _2: int]

scala> ds.dropDuplicates(Seq("_1", "_2"))
res0: org.apache.spark.sql.Dataset[org.apache.spark.sql.Row] = [_1: string, _2: int]

scala> ds.dropDuplicates("_1", "_2")
<console>:26: error: overloaded method value dropDuplicates with alternatives:
  (colNames: Array[String])org.apache.spark.sql.Dataset[org.apache.spark.sql.Row] <and>
  (colNames: Seq[String])org.apache.spark.sql.Dataset[org.apache.spark.sql.Row] <and>
  ()org.apache.spark.sql.Dataset[org.apache.spark.sql.Row]
 cannot be applied to (String, String)
       ds.dropDuplicates("_1", "_2")
          ^

Issue Links

• relates to: SPARK-15908 Add varargs-type dropDuplicates() function in SparkR
• links to: [Github] Pull Request #13545 (dongjoon-hyun)