DataFrame-ified zipWithIndex

Question

I am trying to solve the age-old problem of adding a sequence number to a data set. I am working with DataFrames, and there appears to be no DataFrame equivalent to RD

Answer 1

The following was posted on behalf of the David Griffin (edited out of question).

The all-singing, all-dancing dfZipWithIndex method. You can set the starting offset (which defaults to 1), the index column name (defaults to "id"), and place the column in the front or the back:

import org.apache.spark.sql.DataFrame
import org.apache.spark.sql.types.{LongType, StructField, StructType}
import org.apache.spark.sql.Row


def dfZipWithIndex(
  df: DataFrame,
  offset: Int = 1,
  colName: String = "id",
  inFront: Boolean = true
) : DataFrame = {
  df.sqlContext.createDataFrame(
    df.rdd.zipWithIndex.map(ln =>
      Row.fromSeq(
        (if (inFront) Seq(ln._2 + offset) else Seq())
          ++ ln._1.toSeq ++
        (if (inFront) Seq() else Seq(ln._2 + offset))
      )
    ),
    StructType(
      (if (inFront) Array(StructField(colName,LongType,false)) else Array[StructField]()) 
        ++ df.schema.fields ++ 
      (if (inFront) Array[StructField]() else Array(StructField(colName,LongType,false)))
    )
  ) 
}