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-2.2.1.180	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.179	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.178	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.177	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.176	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.175	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.174	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.173	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.172	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.171	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.170	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.169	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.167	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.166	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.165	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.164	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.163	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.162	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.161	tracks/scala/exercises/luhn/example.scala
trackler-2.2.1.160	tracks/scala/exercises/luhn/example.scala