jdegoes

Applied Functional Programming with Scala - Notes

Copyright © 2016-2018 Fantasyland Institute of Learning. All rights reserved.

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

pathikrit

class NorvigSpellChecker(corpus: String, alphabet: Seq[Char] = 'a' to 'z', level: Int = 2) {
  val words = s"[${alphabet.head}-${alphabet.last}]+".r.findAllIn(corpus.toLowerCase).toSeq

  val count = words.groupBy(_.toSeq).mapValues(_.size) withDefaultValue 0

  def edit(n: Int)(word: Seq[Char]): Set[Seq[Char]] = n match {
    case 0 => Set(word)
    case 1 =>
      val splits = word.indices map word.splitAt
      val deletes = splits collect {case (a, b0 +: b1) => a ++ b1}