Scala for the Impatient

Scala Basics

Copyright © Cay S. Horstmann 2015

Know the story behind Scala

Why Scala?

Scala Levels of Expertise

These lessons are A1 unless noted otherwise.

Application Programmer Library Designer Overall Scala Level
Beginning A1 Beginning
Intermediate A2 Junior L1 Intermediate
Expert A3 Senior L2 Advanced
Expert L3 Expert

Use Scala worksheets

Live demo of worksheets

Work with values, variables, and fundamental data types

Declaring Variables

Commonly Used Types

Invoke functions and methods

Calling Functions and Methods

Work with Scaladoc


Practice using the worksheet, invoking functions, and reading Scaladoc


Scary looking lab

Part 1: The Scala Worksheet

  1. Start the Scala IDE and make a new Scala project: File → New → Scala Project.
    Give a name Lesson1.
    Right-click on the project in the Package Explorer, then select New → Scala Worksheet. Call it Sheet1.
    Select Project from the menu and uncheck the Build Automatically checkbox.
    Make a new line before the } . Type 6 * 7 and then save (Ctrl+S/⌘+S). What do you get?
  2. Edit the line to read val a = 6 * 7 and save. What do you get?
  3. Add a. What do you get?
  4. Add a = 43. What do you get? Why?
  5. Remove that line and add val b; (This time with a semicolon.) What do you get? Why?
  6. Change the line to val b: BigInt = 6 * 7. What do you get?
  7. Add b.pow(1000). What do you get?

Part 2: Functions

  1. Type import scala.math._ just above the }.
  2. Below the import statement, type:
    What do you get?
  3. Type What do you get?
  4. Type What do you get?
  5. Type 6.*(7). What do you get? Why?

Part 3: Scaladoc

  1. Open Scaladoc:
    Click on Int, then click on the large C icon. Watch it turn into an O.
    What is the Scala analog of java.lang.Integer.MAX_VALUE?
  2. Type Str into the search box (next to the magnifying class Icon).
    Click on StringOps.
    Read the description of distinct.
    What do you expect the result of "Mississippi".distinct to be?
  3. Try it out in the worksheet. Is that what you got?
  4. Read the description of permutations.
    What do you expect the result of "Rhine".permutations to be?
  5. That's not so good. Add .toArray. Now what do you get?
  6. What do you get for "ABC".sum? Why? (Hint: Try 'A'.toInt and "ABC".sum.toInt)