bing
Flat 10% & upto 50% off + 10% Cashback + Free additional Courses. Hurry up
×
UPTO
50%
OFF!
Intellipaat
Intellipaat
  • Live Instructor-led Classes
  • Expert Education
  • 24*7 Support
  • Flexible Schedule

 

Pattern Matching

It is a generalization of C or Java’s switch statement. In this match method is used instead switch statement. It is defined in Scala’s root class Any and therefore is available for all objects. The match method takes a number of cases as an argument. Each alternative takes a pattern and one or more expressions which will be performed if the pattern matches. A symbol => is used to separate the pattern from the expressions.

e.g.

object Intellipaat {

def main(args: Array[String]) {

println(matchValue(2))

}

def matchValue(i: Int): String = i match {

case 1 => "one"

case 2 => "two"

case 3=> "three"

case _=> "unknown"

}

}

Output

two

If patterns are of different type in different cases the use Any except Int and String in above example.

 

Case Classes

These are the special types of classes which are used for pattern matching with case expressions. By adding case keyword there are number of advantages which are:

  • Compiler automatically changes the constructor arguments into immutable fields.
  • Compiler automatically includes equals, hashCode and toString methods to the class

Syntax

case class Calculator(Value: Type)

e.g.

object Intellipaat {

def main(args: Array[String]) {

val a = new employee(1, “abc”)

val b  = new employee(2, “xyz”)

val c  = new employee(3, “pgr”)

for (employee <- List(a, b, c)) {

employee match {

case employee(1, “abc”) => println("Hello abc")

case employee(2, “xyz”) => println(“Hello xyz”)

case employee(id, employee_name) => println("ID: " +id + ", Employee:" + employee_name)

}

}

}

case class employee(id: Int, employee_name: String) // case class

}

Output

Hello abc

Hello xyz

ID: 3, Employee: pqr

 

Previous Next

Download Interview Questions asked by top MNCs in 2018?

Learn SQL in 16 hrs from experts



"0 Responses on Pattern Matching and Case Classes"

100% Secure Payments. All major credit & debit cards accepted Or Pay by Paypal.
top

Sales Offer

Sign Up or Login to view the Free Pattern Matching and Case Classes.