iboss-ptk

println(scala.io.Source.fromFile("assgn.txt").toList.map( x => if( "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toList contains x ) (("ABCDEFGHIJKLMNOPQRSTUVWXYZ".toList zip "GHIDDKLMNOFPMRSCTEUVBWXYYA".toList)(scala.collection.breakOut): Map[Char, Char])(x) else x ).mkString)

iboss-ptk

// Use Gists to store code you would like to remember later on
console.log(window); // log the "window" object to the console

iboss-ptk

case class Book(
  id: Int, name: String, authors: List[String], rating: Double)

val books = List(
  Book(1, "The Pragmatic Programmer", 
    List("Andrew Hunt", "Dave Thomas"), 4.3), 
  Book(2, "Lean Startup", List("Eric Ries"), 4.5), 
  Book(3, "Clean Code", List("Robert C. Martin"), 3.1), 
  Book(4, "Agile Software Development, Principles, Patterns, and Practices",
    List("Robert C. Martin"), 4.5),

iboss-ptk

// map each element to a key-value pair of id and the book object itself
val bookMap = books.map(book => (book.id, book)).toMap

bookMap(1) // => Book(1,The Pragmatic Programmer,List(Andrew Hunt, Dave Thomas),4.3)

iboss-ptk

val authors = books.flatMap(book => book.authors).toSet
// => Set(Andrew Hunt, Eric Ries, Blake Masters, Robert C. Martin, Peter Thiel, Dave Thomas)

iboss-ptk

val fourOrMoreRatingBooks = books
  .filter(book => book.rating > 4.0)
  .map(book => book.name)
  
// => List(The Pragmatic Programmer, Lean Startup, 
//        Agile Software Development, Principles, Patterns, and Practices, From Zero to One)

iboss-ptk

val numbers = List(1,2,3,4,5)

numbers.reduce((acc, curr) => acc + curr) // => 15
numbers.foldLeft(0)((acc, curr) => acc + curr) // => 15

iboss-ptk

val accumulatingList = numbers
  .foldLeft(List[Int]())((acc, curr) => 
    if(!acc.isEmpty) acc :+ (acc.last + curr) else acc :+ curr)
// => List(1, 3, 6, 10, 15)

def contains(numbers: List[Int], target: Int) = 
  numbers.foldLeft(false)((acc, curr) => if(curr == target) true else acc || false)

contains(numbers, 4) // => true
contains(numbers, 20) // => false

iboss-ptk

def dotProduct(vector1: Vector[Double], vector2: Vector[Double]) =
  vector1.zip(vector2)
    .map(v => v._1 * v._2)
    .reduce((acc, curr) => acc + curr)
		
val vector1 = Vector(1.7, 2.3, 4.0)
val vector2 = Vector(2.4, 1.3, 5.1)

dotProduct(vector1, vector2) // => 27.47

iboss-ptk

List(1, 2, 3) zip List(1, 1)
// => List((1,1), (2,1))