Data commit

Task/Middle-three-digits/Scala/middle-three-digits.scala

@@ -0,0 +1,21 @@
+/**
+ * Optionally return the middle three digits of an integer.
+ *
+ * @example List(123,12345,-789,1234,12) flatMap (middleThree(_)), returns: List(123, 234, 789)
+ */
+def middleThree( s:Int ) : Option[Int] = s.abs.toString match {
+  case v if v.length % 2 == 0   => None   // Middle three is undefined for even lengths
+  case v if v.length < 3        => None
+  case v                        => 			
+    val i = (v.length / 2) - 1
+    Some( v.substring(i,i+3).toInt )
+}
+
+
+// A little test...
+val intVals = List(123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345,1,2,-1,-10,2002,-2002,0)
+
+intVals map (middleThree(_)) map {
+  case None => "No middle three"
+  case Some(v) => "%03d".format(v)  // Format the value, force leading zeroes
+} mkString("\n")