What is case class in Scala syntax of case class?

Asked By: Jemma Lagueruela | Last Updated: 9th May, 2020
Category: technology and computing programming languages
4.3/5 (150 Views . 17 Votes)
Scala case classes are just regular classes which are immutable by default and decomposable through pattern matching. It uses equal method to compare instance structurally. It does not use new keyword to instantiate object. All the parameters listed in the case class are public and immutable by default.

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Also to know is, what is a case class in Scala?

Case classes are regular classes which export their constructor parameters and which provide a recursive decomposition mechanism via pattern matching. To facilitate the construction of case class instances, Scala does not require that the new primitive is used. One can simply use the class name as a function.

Also, what is difference between Case class and class in Scala? We saw the main differences between classes and case classes. It turns out that case classes are just a special case of classes, whose purpose is to aggregate several values into a single value. So, when we define a case class, the Scala compiler defines a class enhanced with some more methods and a companion object.

Furthermore, what does case class mean?

A Case Class is just like a regular class, which has a feature for modeling unchangeable data. It is also constructive in pattern matching. Note: The Case class has a default apply() method which manages the construction of object.

Can case class have methods?

case classes are used to conveniently store and match on the contents of a class. You can construct them without using new. case classes automatically have equality and nice toString methods based on the constructor arguments. case classes can have methods just like normal classes.

27 Related Question Answers Found

What is difference between class and object in Scala?

Defining an object in Scala is like defining a class in Java that has only static methods. However, in Scala an object can extend another superclass, implement interfaces, and be passed around as though it were an instance of a class. (So it's like the static methods on a class but better).

What are Scala traits?

In scala, trait is a collection of abstract and non-abstract methods. You can create trait that can have all abstract methods or some abstract and some non-abstract methods. Traits are compiled into Java interfaces with corresponding implementation classes that hold any methods implemented in the traits.

How do you define a class in Scala?

Class and Object in Scala
  1. Keyword class: A class keyword is used to declare the type class.
  2. Class name: The name should begin with a initial letter (capitalized by convention).
  3. Superclass(if any):The name of the class's parent (superclass), if any, preceded by the keyword extends.

What is the difference between a trait and an abstract class?

Abstract class contain constructor parameters. Traits are completely interoperable only when they do not contain any implementation code. Abstract class are completely interoperable with Java code. Traits are stackable.

Is Scala object oriented?

Scala is a functional programming language, but it is also an object-oriented programming language like Java, Python, Ruby, Smalltalk, and others. On the other hand, Scala's OO model provides tools for designing composable, reusable modules, which are essential for larger applications.

What is some in Scala?

Scala Option[ T ] is a container for zero or one element of a given type. For instance, the get method of Scala's Map produces Some(value) if a value corresponding to a given key has been found, or None if the given key is not defined in the Map.

Are Case classes serializable?

Case classes (and case objects) in Scala are inherently serializable. This is a good thing but it can have unforeseen consequences if your case class is mutable. Let's say you create a case class which has a mutable field (or variable).

What is the use of case class in spark?

The Scala interface for Spark SQL supports automatically converting an RDD containing case classes to a DataFrame. The case class defines the schema of the table. The names of the arguments to the case class are read using reflection and they become the names of the columns.

What is the use of case class?

A case class gives you "free" (i.e., you don't have to write) implementations of equals , hashcode and toString , as well as apply and unapply in the companion object. Basically, you can think of a case class as a named tuple, whose fields are named as well.

What is a case object?

A case object is a singleton case class. They are used kind of like enumeration values. It can be used in pattern matching just like any other value: TaxCalculationTimeout match { case TaxCalculationTimeout => println("hello") } When you define a case class, you are creating a template for instances of that class.

What is implicit class in Scala?

Scala 2.10 introduced a new feature called implicit classes. An implicit class is a class marked with the implicit keyword. This keyword makes the class's primary constructor available for implicit conversions when the class is in scope. Implicit classes were proposed in SIP-13.

What is singleton object in Scala?

Instead of static keyword Scala has singleton object. A Singleton object is an object which defines a single object of a class. A singleton object provides an entry point to your program execution. If you do not create a singleton object in your program, then your code compile successfully but does not give output.

What is abstract class in Scala?

A class which is declared with abstract keyword is known as abstract class. Abstract class is used to achieve abstraction. Abstraction is a process in which we hide complex implementation details and show only functionality to the user. In scala, we can achieve abstraction by using abstract class and trait.

What does case do in Scala?

The case keyword tells the compiler to add additional features automatically. The compiler automatically converts the constructor arguments into immutable fields. The val keyword is optional. If mutable fields are needed the var keyword can be used.

What is Apply method in Scala?

Wikipedia. apply serves the purpose of closing the gap between Object-Oriented and Functional paradigms in Scala. Every function in Scala can be represented as an object. Every function also has an OO type: for instance, a function that takes an Int parameter and returns an Int will have OO type of Function1[Int,Int] .

What is constructor in Scala?

Scala constructor is used for creating an instance of a class. There are two types of constructor in Scala – Primary and Auxiliary. Not a special method, a constructor is different in Scala than in Java constructors. The class' body is the primary constructor and the parameter list follows the class name.

What is pattern matching in Scala?

Scala | Pattern Matching. Pattern matching is a way of checking the given sequence of tokens for the presence of the specific pattern. It is a technique for checking a value against a pattern. It is similar to the switch statement of Java and C. Here, “match” keyword is used instead of switch statement.