Case Classes can be seen as plain and immutable data-holding objects that should exclusively depend on their constructor arguments.
- Case classes can be pattern matched
- Case classes automatically define hashcode and equals
- Case classes automatically define getter methods for the constructor arguments
For example:
def describe(x: Any) = x match {
case 5 => "five"
case true => "truth"
case "hello" => "hi!"
case Nil => "the empty list"
case _ => "something else"
}
Sequence patterns
You can match against sequence types like List or Array just like you match against case classes:
expr match {
case List(0, _, _) => println("found it”) //change this to List(0, _*) if you don’t want to specify how long it should be
case _ =>
}
Typed patterns
You can use a typed pattern as a convenient replacement for type tests and type casts:
def generalSize(x: Any) = x match {
case s: String => s.length
case m: Map[_, _] => m.size
case _ => -1
}
Patterns in for expressions
for ((country, city) <- capitals)
println("The capital of "+ country +" is "+ city)
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