Scala - Conditional Expressions and Pattern Matching

Scala Conditional Expressions

If statement

if(condition){  
    // Statements to be executed when the condition is true
}

If-else statement

if(condition){  
    // If block statements to be executed when the condition is true
} else {  
    // Else block statements to be executed when the condition is false
}

Nested if-else statement

if(condition){  
    // If block statements to be executed when the condition is true
    if(conditionX){  
       // If block statements to be executed when the conditionX is true
   } else {  
       // Else bock statements to be executed when the conditionX is false
   }  
} else {  
    // Else block statements to be executed  
}

If-else-if ladder statement

if (conditionX){    
   //Statements to be executed when conditionX is true
} else if (conditionY){    
   //Statements to be executed when conditionY is true
...
else {    
   //Statements to be executed when all the conditions are false
}

Alternative of Ternary Operators as Scala If Statement
- Scala does not have ternary operator concept like C/C++.
- It provides more powerful "if statement" which can return value and whose return value can be assigned to a function.

object HelloObject {
  def main(args : Array[String]){
    var status=Numcheck(-20)
    println(status)
  }
  def Numcheck(a:Int)= if(a>=0) "Positive" else "Negative"
}
OUTPUT :: Negative

++++++++++++++++++++++++++

Scala Pattern Matching

-Pattern matching is same as switch case.
-It matches the best case available in the pattern. [Example-1]
-Match expression can also return case value and the returned case value can also be assigned to a function. [Example-2]
-We can define method having a match with cases for any type of data. [Example-3]

object HelloObject1 {
  def main(args: Array[String]): Unit = {
    //Scala Pattern Matching Example-1    
    var grade = 'A'    
    grade match {
      case 'O' => println("Outstanding")
      case 'E' => println("Excellent")
      case 'A' => println("Good")
      case 'B' => println("Average")
      case _ => println("Fail")
    }
  }
}

OUTPUT : Good

+++++++++++++

object HelloObject2 {
  def main(args : Array[String]): Unit = {
    //Scala Pattern Matching Example-2
    println(myGrade('E'))
  }
  def myGrade(grade : Char) : String = grade match{
    case 'O' => "Outstanding"
    case 'E' => "Excellent"    case 'A' => "Good"
    case 'B' => "Average"    case _   => "Fail"  }
}

OUTPUT : Excellent

+++++++++++++
-Any is a class in scala which is a super class of all data types and deals with all type of data.
-Let's see an example.
------------
Example-2::
object HelloObject6 {

def main(args : Array[String]): Unit = {
var result = search("Hello")
println(result)

}
def search(x:Any):Any= x match{
case 1 => "One"
case 2 => "Two"
case "Hello" => "Hello world"
case _ => "Other"
}
}

Scala - Conditional Expressions and Pattern Matching