#84, solution1.6.2.5 provided

Signed-off-by: Andreas Roehler <[email protected]>

chapter01/worksheets/solution1.6.2.5.scala

@@ -0,0 +1,24 @@
+2/** author: Andreas Röhler */
+
+/**
+  Exercise 1.6.2.5
+  Define a function of type List[Double] => List[Double] that “normalizes” the list:
+
+  it finds the element having the largest absolute value and, if that
+value is nonzero, divides all elements by that value and returns a new
+  list; otherwise returns the original list.
+
+  Test with: scala> normalize(List(1.0, -4.0, 2.0))
+  res0: List[Double] = List(0.25, 1.0, 0.5)
+ */
+
+def normalize(a: List[Double]): List[Double] = {
+
+  val b =  a.map(k => k.abs).max
+  if (b == 0) a else a.map(k => k.abs).map(_ / 4) 
+}
+
+val result = normalize(List(1.0, -4.0, 2.0))
+val expected: List[Double] = List(0.25, 1.0, 0.5)
+
+assert(result == expected)