Updated April 20, 2023
Introduction to Scala Some
Scala some class is closely related to Option class in scala. We use Option class in scala when the value of object can be null. To handle this we have two child classes of Option class in scala which are Some and None. Whenever we return any value from the Option it can either be instance of some or None. As we know these both classes are child classes of Option so while using it our method will return the Instance of Option only. If we get the value of object then this Option will return instance of Some class, if we do not get value for object then this Option class will return value of None class in scala.
Syntax:
defmethod_name(in: Data_type): Option[Data_type] = {
try {
Some() /// logic goes here ...
} catch {
// logic here
}
}We can always use some with Option as they both related.We can see one practice syntax to understand it better see below;
defdemofun(a: Int): Option[String] = {
try {
Some(a == 0)
} catch {
case x: Exception => None
}
}In this syntax we are defining one function with name demofun which is taking an Integer and returning Option instance which can be either an instance of Some class or None class in scala. After defining this we can write our own logic according to the requirement.
How does Some Class Work 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. We can use this with a method signature and also with a case statement in scala.f we write something using some class then we are sure that it will return some value to us so we are sure and can avoid the null and empty checks as well which will save some lines of code. This class is defined under the scala. Some package. We can have look at some extended class, spertypes and some of the known classes available see below;
1. extended class available in scala;
- Option[A]
- Product
- Serializable
2. Super type classes for some in scala;
- Option[A]
- io.Serializable
- Product
- Equals
- IterableOnce[A]
- AnyRef
- AnyRef
3. Constructor available for some class;
Some class constructor takes one parameter as a value which can be of any type syntax see below;
- Syntax available as per scaladocs ; :: new Some(value: A)
In this, we are creating some instance by using new keyword and passing value inside it these values can be of any type.
4. Some of the methods available for some class in scala are as follows;
- nonEmpty: This method also returnBoolean. It will return true of the object is not empty else false.
- isEmpty: This method is used to check the object id empty or not, it returns a Boolean value. If the object is empty it will return true else false.
- isDefined: This method returnBoolean. It will return true if the object is not empty else false.
- get: This method will return value, if the value is not present then it will return an exception.
- contains: This method is used to check the value present in the input pass or not. This method return a Boolean value true or false. If the value present it will return true else false.
- exists: This method return true if the value exists else false, this method uses predicate on optional value.
- filter: This is used to filter the object. It uses the value which matches the predicate value.
- filterNot: This is used to filter the object. It uses the value which does not match the predicate value.
5. Now we will see one very simple example to use some class in scala for beginners see below;
object Main extends App{
// Your code here!
// using some here
valsomeVal:Option[String] = Some("Hello world !!")
//just printing value
println(someVal)
}In this example we are definingthe some value by mentioning the return type as Option and data type as String followed by the Some instance. After that we are just printing the value which is some holding. We can also use the above method defined with some.
Examples of Scala Some
Following are the examples are given below:
Example #1
In this example we are printingthe some value.
Code:
object Main extends App{
// Your code here!
// using some here
valsomeVal:Option[String] = Some("Hello world !!")
//just printing value
println(someVal)
}Output:
Example #2
In this example we are using isEmpty method to check the some value obtained.
Code:
object Main extends App{
// Your code here!
// using some here
valsomeVal:Option[String] = Some("Hello world !!")
//using method here ..
val result = someVal.isEmpty
//just printing value
println("result obtained is :: " + result)
println(someVal)
}Output:
Example #3
In this example we are using isDefined method to check the some object.
Code:
object Main extends App{
// Your code here!
// using some here
valsomeVal:Option[String] = Some("Hello world !!")
//using method here ..
val result = someVal.isDefined
//just printing value
println("result obtained is :: " + result)
println(someVal)
}Output:
Example #4
In this example we are using getOrElse method with some and none.
Code:
object Main extends App{
// Your code here!
// using some here
valsomeval:Option[Int] = Some(20)
valsomeResult = someval.getOrElse(2)
// using NOne here
valnoneval:Option[Int] = None
valnoneResult = noneval.getOrElse(30)
println("some value obtained ::::" + someResult)
println("none value obtained ::::" + noneResult)
}Output:
Advantages
Some of the advantages are:
- We can easily deal with the null values in our program.
- Do not need to write the Null checks, which reduced the unnecessary checks as well.
Conclusion
These are good way to deal with the object they can always be used with option class in scala. Either it will return instance of None or return an instance of some while working with it. Provide us many methods to work with the collection object as well.
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