Skip to content

Latest commit

 

History

History
49 lines (47 loc) · 2.69 KB

README.md

File metadata and controls

49 lines (47 loc) · 2.69 KB

Iteration1

This project is for learning scala from the book O'Reilly Programming Scala 2nd edition

  1. Setup
  • Installed SBT and Scala
  • reviewd sbt and scala commands
  • reviewed scalac
  • Used SBT REPL & Scala Console
  • Installed Atom text editor
  • Installed scala packages to Atom
  • Setup Project Directory
  • Linked local directory to Github
  1. Programming
  • Chapter 1
    • Created basic class
    • Compiled and ran class in console
    • Created Objects and Main classes
    • Used run sbt command to find mains in directory
  • Chapter 2

    • No need for semicolons since =, { and => are indicators

    • Var is mutable and Val is immutable (ex: val/var array = new Array(2) )

    • You can specify type (ex: var array: Array[String] = new Array(2) )

    • Ranges of numbers (ex: 1 to 10, 1 until 10, 1 to 10 by 3, 1L to 10L by 3 )

    • Partial functions are not defined for all possible inputs but only those that match at least 1 case clause

      • val pf1: PartialFunction[Any,String] = { case s: String => "Yes" }

    • def for method declarations

    • Use future API to execute asynchronously

    • can verify recursion with tailrec import

    • You can infer type

    • Went through literals

    • Optioon[T] is used in map.get where it will return Some(T) or None if there is nothing

    • seal is used to insure that the subclasses are contained within the same source file

    • packages are used so you can easily import all types, values and methods within

    • abstract classes is when members are not all defined -Parameterized Types is where you use List[A], List[+A] (List[B] is subtype), List[-A]( List[B] is parent type)

  • Chapter 3
    • Almost all operator are methods with 1.+(2) or 1.toString and can still use 1 + 2 or 1 toString
    • If you have a method taking no arguments you can leave off the parentheses
      • List(1,2,3,4,5,6).filter((i: Int) => isEven(i)).foreach((i:Int) => println(i)) can go to List(1,2,3,4,5,6) filter isEven foreach println
    • Methods ending with a colon are right associative while all others are left associative
      • 'a' :: list binds a to the left of the list
    • scala if , for , while, do-while, syntax is common but can be assigned to vals
    • scope is expanded to where you can get a val thats declared outside the for
    • You use try catch and finally clauses
    • lazy vals are used to initialized a val once since it is expensive in time, money, etc... and it is deferred until needed
    • You can use Enumerated type to make a type that is complex
    • Interpolated Strings are used where you can print out variable easily (ex: println(s"Hello, $name") where s clarifies a string and $ signifies a variable
    • traits are commonly used for abstractin purposed such as printing out data