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What is none type in Scala?
None is a subtype of Option type. Scala's best practices advise us to wrap the return value in the Option type in cases where the function may not have a return value.
What is any type in Scala?
Scala Type Hierarchy Any is the supertype of all types, also called the top type. It defines certain universal methods such as equals , hashCode , and toString . Any has two direct subclasses: AnyVal and AnyRef . AnyVal represents value types.
Is there null in Scala?
Nothing - at the bottom of the Scala type hierarchy. Null is the type of the null literal. It is a subtype of every type except those of value classes. Value classes are subclasses of AnyVal, which includes primitive types such as Int, Boolean, and user-defined value classes.
What is def main args array string unit in Scala?
def main(args: Array[String]): def is the keyword in Scala which is used to define the function and “main” is the name of Main Method. args: Array[String] are used for the command line arguments. println(“Hello World!”): println is a method in Scala which is used to display the Output on console.
What is a class in Scala?
Classes in Scala are blueprints for creating objects. They can contain methods, values, variables, types, objects, traits, and classes which are collectively called members.
What does => mean in Scala?
function arrow=> is the "function arrow". It is used both in function type signatures as well as anonymous function terms. () => Unit is a shorthand for Function0[Unit] , which is the type of functions which take no arguments and return nothing useful (like void in other languages).
What is lazy in Scala?
Vals and Lazy vals are present in Scala. lazy keyword changes the val to get lazily initialized. Lazy initialization means that whenever an object creation seems expensive, the lazy keyword can be stick before val.
What is some () in Scala?
Scala some class returns some value if the object is not null, it is the child class of option. Basically, the option is a data structure which means it can return some value or None. The option has two cases with it, None and Some. We can use this with the collection.
What are tuples in Scala?
In Scala, a tuple is a value that contains a fixed number of elements, each with its own type. Tuples are immutable. Tuples are especially handy for returning multiple values from a method.
What is args in Scala?
Scala allows you to indicate that the last parameter to a function may be repeated. This allows clients to pass variable length argument lists to the function. Here, the type of args inside the print Strings function, which is declared as type "String*" is actually Array[String].
What is object class in Scala?
An object is a class that has exactly one instance. It is created lazily when it is referenced, like a lazy val. As a top-level value, an object is a singleton. As a member of an enclosing class or as a local value, it behaves exactly like a lazy val.
What is lambda in Scala?
Lambda Expression refers to an expression that uses an anonymous function instead of variable or value. Lambda expressions are more convenient when we have a simple function to be used in one place. These expressions are faster and more expressive than defining a whole function.
What are the differences between any AnyRef and AnyVal?
Any has two direct subclasses: AnyVal and AnyRef. AnyVal represents value types. There are nine predefined value types and they are non-nullable: Double, Float, Long, Int, Short, Byte, Char, Unit, and Boolean. AnyRef represents reference types.
What is either in Scala?
In Scala Either, functions exactly similar to an Option. The only dissimilarity is that with Either it is practicable to return a string which can explicate the instructions about the error that appeared.
What is function type in Scala?
Scala functions are first-class values. Scala functions are first-class values. You must mention the return type of parameters while defining the function and the return type of a function is optional. If you don't specify the return type of a function, the default return type is Unit.
What is type parameter in Scala?
Language. Methods in Scala can be parameterized by type as well as value. The syntax is similar to that of generic classes. Type parameters are enclosed in square brackets, while value parameters are enclosed in parentheses.
What does "to return unit" mean?
To return Unit means the function returns nothing. In other words, you are calling the function for its side-effects rather than for anything it calculates for you. Given your foreach example, here are some functions that might make sense.
Is a scala unit void?
Unit in scala is identical to void in Java, moreover, Java sees Scala's Unit as void, and vise versa. So in java it could be written like:
