Example of finding mean of multiple features in frame object grouped by custom index

frame.scala

import org.saddle._

object Main {
  def main(args: Array[String]) {
    
    // Requires *.sbt file including saddle dependency to run. Run from command line with `sbt run frame.scala`
    val height: Series[String, Double] = Series("Male" -> 6.0, "Male" -> 5.92, "Male" -> 5.58, "Male" -> 5.92, 
    "Female" -> 5.0, "Female" -> 5.5, "Female" -> 5.42, "Female" -> 5.75)
    val weight: Series[String, Double] = Series("Male" -> 180.0, "Male" -> 190.0, "Male" -> 170.0, "Male" -> 165.0, 
    "Female" -> 100.0, "Female" -> 150.0, "Female" -> 130.0, "Female" -> 150.0)
    val foot_size: Series[String, Double] = Series("Male" -> 12.0, "Male" -> 11.0, "Male" -> 12.0, "Male" -> 10.0, 
    "Female" -> 6.0, "Female" -> 8.0, "Female" -> 7.0, "Female" -> 9.0)
    val data = Frame("Height" -> height, "Weight" -> weight, "Foot_Size" -> foot_size)

    println(data.groupBy.combine(_.mean))
    
  }
}