Hi all, I have two questions about selecting columns of Dataset. First, could you tell me know if there is any way to select TypedColumn columns in addition to the combination of `expr` and `as`? Second, how can we alias such a `expr("name").as[String]` Column?
I tried to select a column of Dataset like DataFrame. However, I couldn't do that. ``` case class Person(id: Int, name: String) val df = sc.parallelize(Seq((1, "Bob"), (2, "Tom"))).toDF("id", "name") val ds = df.as[Person] ds.select(expr("name").as[String]).show +-----+ |value| +-----+ | Bob| | Tom| +-----+ ds.select('id).show <console>:34: error: type mismatch; found : Symbol required: org.apache.spark.sql.TypedColumn[Person,?] ds.select('id).show') ds.select($"id").show <console>:34: error: type mismatch; found : org.apache.spark.sql.ColumnName required: org.apache.spark.sql.TypedColumn[Person,?] ds.select($"id").show ds.select(ds("id")).show <console>:34: error: org.apache.spark.sql.Dataset[Person] does not take parameters ds.select(ds("id")).show ds.select("id").show <console>:34: error: type mismatch; found : String("id") required: org.apache.spark.sql.TypedColumn[Person,?] ds.select("id").show ``` Best, Yu ----- -- Yu Ishikawa -- View this message in context: http://apache-spark-developers-list.1001551.n3.nabble.com/Is-there-any-way-to-select-columns-of-Dataset-in-addition-to-the-combination-of-expr-and-as-tp15713.html Sent from the Apache Spark Developers List mailing list archive at Nabble.com. --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@spark.apache.org For additional commands, e-mail: dev-h...@spark.apache.org