scalding groupBy

import cascading.tuple.Fields
import com.twitter.scalding._
// groupBy example
class groupBy(args: Args) extends Job(args) {
	val kidsList = List(
		("john", 4, "orange,apple"),
		("liza", 5, "banana,mango"),
		("nina", 5 ,"orange"),
		("x", 4, "none"))
	val orderedPipe =
		IterableSource[(String, Int, String)](kidsList, ('kid, 'age, 'fruits))
		.flatMap('fruits -> 'fruit) { text : String => text.split(",") }
		.discard('fruits)
		.groupBy('fruit) { group => group.size('totalFruits).average('age -> 'averageAge) }
		.debug
		.write(Tsv("Output-groupBy"))
	var kidsList2 = List(
		("john", 4D, "orange,apple"),
		("liza", 5D, "banana,mango"),
		("nina", 5D ,"orange"))
		val kidsSchema = List('kid, 'age, 'fruits)
		val commonGroupOperationsPipe =
	// Csv("kids.tsv" ,"\t", kidsSchema).read
	IterableSource[(String, Int, String)](kidsList, ('kid, 'age, 'fruits))
		.flatMap('fruits -> 'fruit) { text : String => text.split(",") }
		.discard('fruits)
		.groupBy('fruit) { group => group
		.min('age -> 'minAge)
		.max('age -> 'maxAge)
		.average('age -> 'averageAge)
		.sum[Int]('age->'totalAge) // The [Int] is required only in dev versions i.e 0.9.0rc4
		.size('tatalKids)
		.count('age -> 'age4){ x:Int => x == 4 }
		.sizeAveStdev('age -> ('totalAges, 'meanAge, 'stdevAge))
		}
		.debug
		.write(Tsv("Output-commonGroupOperations",writeHeader=true))
	var productList = List(
		("productA", 11.2, 10),
		("productB", 22.5, 22))
		//productList.mkString(",")
	val products =
		IterableSource[(String, Double, Int)](productList, ('productId, 'price, 'quantity))
		.groupBy('productId) { group => group.pass }
		.debug
		.write(Tsv("Output-pgroupBy"))
	val mkString =
		IterableSource[(String, Double, Int)](productList, ('productId, 'price, 'quantity))
		.groupAll { group => group.mkString('productId -> 'productIds, " - ") }
		.debug
		.write(Tsv("Output-mkString", writeHeader=true))
	val sortBy =
		IterableSource[(String, Int, String)](kidsList, ('kid, 'age, 'fruits))
		.flatMap('fruits -> 'fruit) { text : String => text.split(",") }
		.discard('fruits)
		.groupBy('fruit) { group => group.sortBy('age) }
		.debug
		.write(Tsv("Output-sortBy", writeHeader=true))
	// TODO create a unit-test on what happend when we take more than exists
	val take =
		IterableSource[(String, Int, String)](kidsList, ('kid, 'age, 'fruits))
		.flatMap('fruits -> 'fruit) { text : String => text.split(",") }
		.discard('fruits)
		.groupAll { group => group.sortBy('age).take(2) }
		.debug
		.write(Tsv("Output-take", writeHeader=true))
	val takeWhile =
		IterableSource[(String, Int, String)](kidsList, ('kid, 'age, 'fruits))
		.flatMap('fruits -> 'fruit) { text : String => text.split(",") }
		.discard('fruits)
		.groupAll { group => group.takeWhile('age) { x:Int => x <= 4 } }
		.debug
		.write(Tsv("Output-takeWhile", writeHeader=true))
	val sortWithTake =
		IterableSource[(String, Int, String)](kidsList, ('kid, 'age, 'fruits))
		.flatMap('fruits -> 'fruit) { text : String => text.split(",") }
		.discard('fruits)
		.groupAll { group => group.sortWithTake(('age,'kid) -> 'newList, 2) {
		( prev: (Int,String), next:(Int,String)) => prev._1 > next._1
		}}
		.write(Tsv("Output-sortWithTake", writeHeader=true))
	val sortedReverseTake =
		IterableSource[(String, Int, String)](kidsList, ('kid, 'age, 'fruits))
		.flatMap('fruits -> 'fruit) { text : String => text.split(",") }
		.discard('fruits)
		.groupAll { group => group.sortedReverseTake[(Int, String)](( 'age, 'kid) -> 'newList, 2) }
		.debug
		.write(Tsv("Output-sortedReverseTake", writeHeader=true))
}