intro zu options gestrichen bzw. gestrafft

Author: cryptoki

src/main/worksheets/d_Options/a_definition.sc

@@ -0,0 +1,49 @@
+// ====================================
+// Intro
+// ====================================
+val notebookMapOfElvis = Map(
+  "Patricia" -> "Dell", "Rainer" -> "Dell",
+  "Ingo" -> "Apple", "Rainer" -> "Dell")
+
+// TODO -1-  whats happend if the name not exists?
+def getNotebook(teamMember: String): String = {
+  // TODO -2-  can you return a null like in Java?
+  notebookMapOfElvis.get(teamMember).getOrElse("n/a")
+}
+
+// TODO -1-  Implement the getNotebook method
+val ingosNotebook = getNotebook("Ingo")
+println(s"Ingo has a ${ingosNotebook}")
+assert(ingosNotebook == "Apple")
+
+// TODO -2-  Does the getNotebook method work for 'steffensNotebook'?
+val steffensNotebook = getNotebook("Steffen")
+println(s"Steffen has a ${steffensNotebook}")
+
+
+// Option is a ..
+// .. datatype to represent optional values
+// .. value that could be exists or not.
+// solve the NULL check hell in Java
+
+// two implementations of abstract class 'Option'
+
+// ====================================
+// Some
+// ====================================
+// 1  case class Some
+// represents existing values of type
+val some1 = Some(1234)
+
+val some2 = Option.apply(2)
+
+
+// ====================================
+// None
+// ====================================
+
+// 2  case object None
+// represents non-existent values
+val none1 = Option.empty
+
+val none2 = None

src/main/worksheets/d_Options/a_definition_1_intro.sc

@@ -0,0 +1,19 @@
+val notebookMapOfElvis = Map("Patricia" -> "Dell",
+  "Rainer" -> "Dell",
+  "Ingo" -> "Apple",
+  "Rainer" -> "Dell")
+
+// TODO -1-  whats happend if the name not exists?
+def getNotebook(teamMember: String): String = {
+  // TODO -2-  can you return a null like in Java?
+  ???
+}
+
+// TODO -1-  Implement the getNotebook method
+val ingosNotebook = getNotebook("Ingo")
+println(s"Ingo has a ${ingosNotebook}")
+assert(ingosNotebook == "Apple")
+
+// TODO -2-  Does the getNotebook method work for 'steffensNotebook'?
+val steffensNotebook = ???
+println(s"Steffen has a ${steffensNotebook}")

src/main/worksheets/d_Options/a_definition_2_some.sc

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+// Option is a
+// ... datatype to represent optional values
+
+
+// 1  case class Some
+// represents existing values of type
+val some1 = ???
+
+val some2 = ???
+
+// TODO -me- go into the scala class

src/main/worksheets/d_Options/a_definition_3_none.sc

@@ -0,0 +1,10 @@
+// Option is a ..
+// .. datatype to represent optional values
+
+// 2  case object None
+// represents non-existent values
+val none1 = ???
+
+val none2 = ???
+
+// TODO -me- go into the scala class