The presumes you have Scala installed on the local system.
This is just the basics on declaring variables in Scala and what data types are available.
Create file src/main/scala/Playground.scala
with the following.
object Playground extends App { val x: Int = 42 println(x) }
println
will allow us to print to the console.App
allows us to run the file in the command line correctly.val
are immutable - this is the Scala and functional programming way.Say we remove the explicit type:
object Playground extends App { val x = 42 println(x) }
This still works as the compiler infers the type to be an Int
.
Below we will run through a declaration of each type.
object Playground extends App { val x: Int = 42 val y: String = "Hello, Friend!" val z: Boolean = true val a: Char = 'a' // Note single quotes val b: Short = 1234 val c: Long = 1234123412341234L // Note the L - similar to Java longs val d: Float = 2.0f // Note the f - similar to Java val e: Double = 2.14 // No marker needed /* in order to mutate a variable */ var f: Int = 1 f = 2 // this is known as a side effect }
Note that the val
and var
keywords have different meanings. val
is a constant and follows functional, immutable conventions while var
is mutable and changing a mutable variable is known as a side effect.