Contents

object Luhn {

  def valid(numberStr: String): Boolean = {
    val s = numberStr.replace(" ", "")

    s.length > 1 &&
      s.forall(c => c.isDigit) &&
      checksum(s.map(_.asDigit).toList) == 0
  }

  private def checkDigit(number: Long): Int = (number % 10).toInt

  private def addends(digits: List[Int]): List[Int] = {
    val zippedDigits = digits.reverse.zipWithIndex

    zippedDigits.map{case (m, i) => if (isOdd(i)) dbl(m) else m}
  }

  private def checksum(digits: List[Int]): Int = addends(digits).sum % 10

  private def dbl(n: Int) = {
    val dbled = n * 2

    if (dbled < 10) dbled else dbled - 9
  }

  private def isOdd(i: Int) = i % 2 == 1
}

Version data entries

168 entries across 168 versions & 1 rubygems

Version	Path
trackler-2.2.1.98	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.97	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.96	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.95	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.94	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.93	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.92	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.91	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.90	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.89	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.88	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.87	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.86	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.85	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.84	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.83	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.82	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.81	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.80	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.79	tracks/scala/exercises/luhn/example.scala