Data commit

Task/Validate-International-Securities-Identification-Number/Scala/validate-international-securities-identification-number.scala

@@ -0,0 +1,40 @@
+object Isin extends App {
+  val isins = Seq("US0378331005", "US0373831005", "U50378331005",
+    "US03378331005", "AU0000XVGZA3","AU0000VXGZA3", "FR0000988040")
+
+  private def ISINtest(isin: String): Boolean = {
+    val isin0 = isin.trim.toUpperCase
+
+    def luhnTestS(number: String): Boolean = {
+
+      def luhnTestN(digits: Seq[Int]): Boolean = {
+
+        def checksum(digits: Seq[Int]): Int = {
+          digits.reverse.zipWithIndex
+            .foldLeft(0) {
+              case (sum, (digit, i)) =>
+                if (i % 2 == 0) sum + digit
+                else sum + (digit * 2) / 10 + (digit * 2) % 10
+            } % 10
+        }
+
+        checksum(digits) == 0
+      }
+
+      luhnTestN(number.map { c =>
+        assert(c.isDigit, s"$number has a non-digit error")
+        c.asDigit
+      })
+    }
+
+    if (!isin0.matches("^[A-Z]{2}[A-Z0-9]{9}\\d$")) false
+    else {
+      val sb = new StringBuilder
+      for (c <- isin0.substring(0, 12)) sb.append(Character.digit(c, 36))
+      luhnTestS(sb.toString)
+    }
+  }
+
+  isins.foreach(isin => println(f"$isin is ${if (ISINtest(isin)) "" else "not"}%s valid"))
+
+}