Scala’s pattern matching statement is most useful for matching on algebraic types expressed via case classes. Scala also allows the definition of patterns independently of case classes, using unapply methods in extractor objects.
What is the use of case class in pattern matching?
Case classes are especially useful for pattern matching. Notification is an abstract super class which has three concrete Notification types implemented with case classes Email, SMS, and VoiceRecording. Now we can do pattern matching on these case classes:
What is the use of any in Scala?
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 that will be performed if the pattern matches. A symbol => is used to separate the pattern from the expressions.
What is a parameterized type pattern in Scala?
A parameterized type pattern T [a 1 ,…,a n ]. Here, a i can type variable patterns or wildcards. This will match all values matching T for arbitrary instantiations of type variables and wildcards. Parameterized type pattern scala.Array [T 1 ]. Here, T 1 is a type pattern.
What is pattern matching in Java with example?
Pattern matching is a mechanism for checking a value against a pattern. A successful match can also deconstruct a value into its constituent parts. It is a more powerful version of the switch statement in Java and it can likewise be used in place of a series of if/else statements.
Why does this match expression have a type string?
This match expression has a type String because all of the cases return String. Therefore, the function matchTest returns a String. Case classes are especially useful for pattern matching. Notification is an abstract super class which has three concrete Notification types implemented with case classes Email, SMS, and VoiceRecording.
