Scala tut

scalaTut.scala

// filtering alphanumeric with isLetterOrDigit
// convert a char to lower with toLower
val string: String = "A man, a plan, a canal: Panama"
string.toCharArray.filter(_.isLetterOrDigit).map(_.toLower)

// convert a string to lower case
string.toLowerCase()

// ========================================================================= //
//                     partial function demo with chaining                  //
// ========================================================================//
def calculateGradeE: PartialFunction[Double, String] = {
  case mark: Double if mark >= 0 && mark < 30 => "E"
}

def calculateGradeD: PartialFunction[Double, String] = {
  case mark: Double if mark >= 30 && mark < 45 => "D"
}

def calculateGradeC: PartialFunction[Double, String] = {
  case mark: Double if mark >= 45 && mark < 60 => "C"
}

def calculateGradeBSchool1: PartialFunction[Double, String] = {
  case mark: Double if mark >= 60 && mark < 80 => "B"
}

def calculateGradeBSchool2: PartialFunction[Double, String] = {
  case mark: Double if mark >= 60 && mark < 85 => "B"
}

def calculateGradeASchool1: PartialFunction[Double, String] = {
  case mark: Double if mark >= 80 => "A"
}

def calculateGradeASchool2: PartialFunction[Double, String] = {
  case mark: Double if mark >= 85 => "A"
}

val calculateCommonGrade =
  calculateGradeE orElse calculateGradeD orElse calculateGradeC

val calculateGradeForSchool1 =
  calculateCommonGrade orElse calculateGradeBSchool1 orElse calculateGradeASchool1

val calculateGradeForSchool2 =
  calculateCommonGrade orElse calculateGradeBSchool2 orElse calculateGradeASchool2

val school1Grade = List[Double](80, 20, 45, 69, 85)
val resultForSchool1 =
  school1Grade.collect[String](calculateGradeForSchool1)
println(s"result for School1 is ${resultForSchool1}")

val school2Grade = List[Double](80, 20, 45, 69, 80)
val resultForSchool2 =
  school2Grade.collect[String](calculateGradeForSchool2)
println(s"result for School2 ${resultForSchool2}")