2023-07-02

Scala Overview

• What is type of paradigm is scala?
  • Multi paradigm (Functional and Object oriented)
• What is the key difference in terms of types in java vs scala?
  • In Java there are two types
    • Primitive
    • Reference
  • In scala every type is an object
• Write “Hello, World” in scala

object Hello {
	def main(args: Array[String]) = {
		println("Hello, World")
	}
}

• What is the difference between val and var?
  • val cannot be reassigned
  • var can be reassigned
• What is the equivalent of val in java?
  • final
• When is it compulsory to specify the return value of a function?
  • When it is recursive
• What is the return type of a function that doesn’t return anything?
  • Unit
• How to access an element of an array?
  • Using parenthesis
  • arr(5)
• How to increment a variable in scala?
  • i += 1
• Do ++ operators work in scala?
  • No
• Which method is used to loop over an array?
  • foreach
• What is the function signature of foreach?
  • foreach takes a function as its arguement
• How to loop over an array using for

for (arg <- args) {
	println(arg)
}

• In the above case is arg a val or a var?
  • It is a val
  • It cannot be modified
• What is the syntax for using match

myVar match {
	case case1 => <statements>
	case _ => <default>
}

• Suppose you want to print a string with variable values inside them. They require no formatting. What to use?
  • use s"String that needs substitution. $var"
  • $var will be replaced by the value of var
• The same scenario but not it needs to be formatted
  • use f-strings
  • f"The value of tmp is $tmp%.2f"