scala-101

Mastering Scala: Unlock the Power of Functional and Object-Oriented Programming

resource

• https://docs.scala-lang.org

install Scala 3 on your machine

• https://www.scala-lang.org/download

clone the project onto your local machine.

cd $HOME && git clone https://github.com/keramiozsoy/scala-101.git && cd scala-101

check version

scala --version

Output

Scala code runner version 3.3.0 -- lsCopyright 2002-2023, LAMP/EPFL

scala-repl

• the scala repl ( READ - EVALUATE - PRINT - LOOP ) is a command-line interpreter that you use a test your scala code on terminal.

• open terminal to open repl

scala

• code

1 + 2

• ouput

val res0: Int = 3

• code

var a = 2 * 5

• output

var a: Int = 10

create your first scala program with sbt tool

• The sbt help to run our project when we have one or multiple files

cd $HOME

• create project

sbt new scala/scala3.g8

• enter project name like below

hello-world

• go to file that have .sbt extension

cd hello-world

sbt clean && sbt run

Hello world!
I was compiled by Scala 3. :)

var type

• var type is immutable.

• run below code. value of variable is changed.

  var a = 0;
  
  a = 5;

cd $HOME/scala-101/var-type

sbt clean && sbt run

val type

• val type is immutable.

• run below code which wil not work.

  val a = 0

  a = 5; // wrong

cd $HOME/scala-101/val-type/src/main/scala

sbt clean && sbt run

declaring variable

If you dont want to give type, compiler will understand, no problem

  // explicit
  val a:Int = 1

  // implicit; the compiler infers the type
  val b = 2 

cd $HOME/scala-101/declaring-variable 

sbt clean && sbt run

strings

• You can use one character or sentence or multiline to define.

  val first = "AAAA"  // String

  println(first)

  val second = 'B'  // Char

  println(second)

  println(s"Result: $first and $second")  // combine string and char

  println(s"Calculate: ${3 * 5} ") // 

  val multiline = """AAA
                  BBBBB
                      CCCC"""
  println(multiline)

• output

AAAA
B
Result: AAAA and B
Calculate: 15
AAA
                  BBBBB
                      CCCC

cd $HOME/scala-101/strings

sbt clean && sbt run

if else condition

• The if/else statement executes a block of code if a specified condition is true. If the condition is false, another block of code can be executed.

  val x = 10
  if x < 0 then
    println("x is negative")
  else if x == 0 then
    println ("x is zero")
  else
    println("x is positive")

• output

x is positive

cd $HOME/scala-101/if-else

sbt clean && sbt run

for loop condition

• let's assume that we have got list of numbers and, we will print all values. for condition helps to do it.

• for -> it starts loop

• do -> to do something while for loop continue, like body of for loop

cd $HOME/scala-101/for-loop

sbt clean && sbt run

for loop guards condition

• Guards which helps when you need to use multiple if expression on for loop.

cd $HOME/scala-101/for-loop-guards

sbt clean && sbt run

for loop yield condition

• using yield keyword ( instead of do keyword ) will returns a result after completing of for loop iterations.

cd $HOME/scala-101/for-loop-yield

sbt clean && sbt run

match condition

• it helps to find result from options

cd $HOME/scala-101/match-condition

sbt clean && sbt run

try-catch-finally

• It is control structure lets you catch exceptions.

cd $HOME/scala-101/try-catch-finally

sbt clean && sbt run

while

• It seems like other loop, (for) it stops loop when condition is founded.

cd $HOME/scala-101/while

sbt clean && sbt run

domain modeling ( TODO )

• Scala supports two paradigms. The paradigm means a way of looking at something, set of idea.
• First paradigm is object-oriented programming
• Second paradigm is functional programming.
• We will look at these paradigm later on.

methods

A method means a function takes parameters and return a value.

def methodName(param1: Type1, param2: Type2): ReturnType =

cd $HOME/scala-101/methods

sbt clean && sbt run

functions