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Posted to user@spark.apache.org by to...@gmail.com on 2017/06/15 09:54:07 UTC

Create dataset from dataframe with fewer columns

Is it possible to concisely create a dataset from a dataframe with fewer columns? Specifically, suppose I create a dataframe with:
val df: DataFrame  = Seq(("v1"),("v2")).toDF("f1")

Then, I have a case class for a dataset defined as:
case class CC(f1: String, f2: Option[String] = None)

I’d like to use df.as[CC] to get an instance of the case class, but this gives me the following error:
org.apache.spark.sql.AnalysisException: cannot resolve '`f2`' given input columns: [f1];

Is there a concise way to use the default values as defined by the case class so that I don't have to explicitly add those columns to the dataframe before converting to a dataset?

Warmest Regards,
Jason Tokayer, PhD
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