Scala and Spark for Big Data Analytics

Implicit in Scala

Implicit is another exciting and powerful feature introduced by Scala, and it can refer to two different things:

• A value that can be automatically passed
• Automatic conversion from one type to another
• They can be used for extending the capabilities of a class

Actual automatic conversion can be accomplished with implicit def, as seen in the following example (supposing you are using the Scala REPL):

scala> implicit def stringToInt(s: String) = s.toIntstringToInt: (s: String)Int

Now, having the preceding code in my scope, it's possible for me to do something like this:

scala> def add(x:Int, y:Int) = x + yadd: (x: Int, y: Int)Intscala> add(1, "2")res5: Int = 3scala>

Even if one of the parameters passed to add() is a String ...