add /ScalaBasic/mapOpDemo_3.scala

README.md

@@ -127,6 +127,7 @@
 	- map (op)
 		- [mapOPDemo_1](src/main/scala/ScalaBasic/mapOpDemo_1.scala)
 		- [mapOpDemo_2](src/main/scala/ScalaBasic/mapOpDemo_2.scala)
+		- [mapOpDemo_3](src/main/scala/ScalaBasic/mapOpDemo_3.scala)
 	- FlatMap
 		- flatMap will go to `every sub group` in a group and map the operation on each of them then return the result
 		- [FlatMapDemo_1](./src/main/scala/ScalaBasic/FlatMapDemo_1.scala)

src/main/scala/ScalaBasic/mapOpDemo_3.scala

@@ -0,0 +1,28 @@
+package ScalaBasic
+
+/**  mapOpDemo_3 : demo how to explicitly declare var type when do mapping*/
+
+
+object mapOpDemo_3 extends App {
+
+  val x = List(1,2,3,4,5)
+
+  val x_1= x.map(x => x+1)
+  println(x_1)
+
+  println("================")
+
+  // *** NOTE : via `(x:Int)` syntax, we can define var type explicitly in mapping
+  val x_2= x.map( (x:Int) => x+1)
+  println(x_2)
+
+  println("================")
+
+  val y = List("a","b","c")
+  val y_1 = y.map(x => x + "-")
+  println(y_1)
+
+  // *** NOTE : via `(x:String)` syntax, we can define var type explicitly in mapping
+  val y_2 = y.map( (x:String) => x + "-")
+  println(y_2)
+}