Installation

I am performing this on MAC with M1 chip. The process can be a little different for other operatiing system/architecture.

1. Install Java - JDK from this locatiion (https://www.oracle.com/java/technologies/downloads/#jdk18-mac)

2. Open terminal or command prompt to check the java version and verify that it is installed properly

java –version

Expected output: Version may vary.

java 18.0.1 2022-04-19
Java(TM) SE Runtime Environment (build 18.0.1+10-24)
Java HotSpot(TM) 64-Bit Server VM (build 18.0.1+10-24, mixed mode, sharing)

3. Now it’s time to install scala. On mac use the following command to install scala. brew install scala

4. Verify scalal version with the following command: scala -version

Scala code runner version 2.13.8 -- Copyright 2002-2021, LAMP/EPFL and Lightbend, Inc.

Basics

Types

Scala does not have built-in/primitive types. It has set of classes to represent supporting types.

Types in scala:

1. Int
2. Long
3. Short
4. Double
5. Float
6. String
7. Byte
8. Char
9. Unit (Similar to void in Java)

Variables

In scala, variables can be declared in 3 different ways.

1. Immutable - Value of such variables can not be altered

val count: Int = 5

NOTE: Changing the value will give error in the ide : Reassignment to val.

2. Mutable - Value of such variables can be altered

var note: String = "Note"
note = "my Note"

3. Lazy Initialization - Value initialized at the time of execution

lazy val myName: String = "my

Type Inference Scala compiler can detect the type of the varibales defined if the type is not mentioned explicitely.

In such case the above example will look like this:

val count = 5

Scala compiler will know that the type of count is Int.

String Interpolation

There are 3 ways to achieve this as per the documentation.

1. s string interpolation

val name = "vasav"
println(s"my name is $name")

2. f string interpolation (Type Safe)

val name = "vasav"
println(f"my name is $name%s")

3. raw string interpolation (It does not do any escaping)

println(s"example of \n s-interpolation")
println(raw"example of \n raw-interpolation")

Output

example of 
 s-interpolation
example of \n raw-interpolation

Conditional Statements

1. if statement

val myNum = 5
//Syntax1
if (myNum == 5) println("They are equal")
//Syntax2
if (myNum == 5){
    println("They are equal")
}

2. if - else statement

//syntax1
if(myNum % 2 == 0) {
    println("even")
} else {
    println("odd")
}

//syntax2
if(myNum % 2 == 0)
    println("even")
else
    println("odd")

3. else if statement

var mode = 4
if(mode == 1){
    println("mode1")
}else if(mode == 2){
    println("mode 2")
}else{
    println("mode 3")
}

In scala, we can directly assign the value of if else to a variable as per the documentation.

val minValue = if (a < b) a else b

Loops

Example of a simple for loop in scala.

for(i <- 1 to 5){
    println(i)
}

Output:

1
2
3
4
5

Important thing to notice here is that, 5 is also included in the loop. Now in order to run the loop till 4, we’ll make a small change. More details on the range can be found on this link.

for(i <- 1 until  5){
    println(i)
}

Output:

1
2
3
4

Scala for loop allows to filter the values as well. An example for the same is provided here which will make things more clear:

var my_list = List("abc","def","ghi","xyz")
for (combination <- my_list if combination == "xyz"){
    println("we have xyz in the list")
}

Output:

we have xyz in the list

Example of while in scala.

var n: Int = 5
while (n > 0){
    println(n)
    n -= 1
}

Output:

5
4
3
2
1

Here we have declared a variable n. Here n is mutable. In the while we check for the condition, if n > 0 then execute the code block. As we can see from the output, the loop will iterate from 5 to 1. When the value on n becomes 0, the condition n > 0 will not be satisfied, so the while block will not get executed.

Example of do while in scala. This is very similar to while but the main differece being the do while will execute at least once.

var n1: Int = 0
do{
    println(n1)
    n1 += 1
}while(n1 > 5)

Output:

0

References

1. http://allaboutscala.com/
2. https://docs.scala-lang.org/overviews/core/string-interpolation.html
3. https://docs.scala-lang.org/overviews/scala-book/if-then-else-construct.html
4. https://docs.scala-lang.org/overviews/scala-book/for-loops.html
5. http://allaboutscala.com/tutorials/chapter-2-learning-basics-scala-programming/scala-tutorial-learn-use-range-inclusive-exclusive/