Scala for H₂O: Shalala¶

help
ncol <frame>
nrow <frame>
head <frame>
tail <frame>
f(2)           - returns 2. column
f("year")      - returns column "year"
f(*,2)         - returns 2. column
f(*, 2 to 5)   - returns 2., 3., 4., 5. columns
f(*,2)+2       - scalar operation - 2.column + 2
f(2)*3         - scalar operation - 2.column * 3
f-1            - scalar operation - all columns - 1
f < 10         - transform the frame into boolean frame respecting the condition

keys              - shows all available keys i KV store
parse("iris.csv") - parse given file and return a frame
put("a.hex", f)   - put a frame into KV store
get("b.hex")      - return a frame from KV store
jobs              - shows a list of executed jobs
shutdown          - shutdown H2O cloud

f map (Add(3))   - call of map function of all columns in frame
                    - function is (Double=>Double) and has to extend Iced
f map (Less(10)) - call of map function on all columns
                    - function is (Double=>Boolean)

sbt compile

sbt run

sbt runExamples

val f = parse("smalldata/cars.csv")

f(2)           // number of cylinders

f("year")      // year of production

f(*, 0::2::7::Nil)  // year,number of cylinders and year

f(7) map Sub(1000) // Subtract 1000 from year column

f("cylinders") map (new BOp {
    var sum:scala.Double = 0
    def apply(rhs:scala.Double) = { sum += rhs; rhs*rhs / sum; }
  })