Flatten Apache Spark Data Frame

gistfile1.txt

import org.apache.spark.sql.Column
import org.apache.spark.sql.types.StructType
import org.apache.spark.sql.functions.col

def flattenSchema(schema: StructType, prefix: String = null) : Array[Column] = {
  schema.fields.flatMap(f => {
    val colName = if (prefix == null) f.name else (prefix + "." + f.name)

    f.dataType match {
      case st: StructType => flattenSchema(st, colName)
      case _ => Array(col(colName))
    }
  })
}

val flattenedSchema = flattenSchema(df.schema)
val renamedCols = flattenedSchema.map(name => col(name.toString()).as(name.toString().replace(".","_")))
val flatDF = df.select(renamedCols:_*)