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Learn Ruby from Scratch

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The Big Picture

Programming is Creation Ruby is Object Oriented

Variables

What are Variables?Reusing Variable Names Things on the Right Go First Quiz on Variables

Built-in Class: Numeric

Working with Numbers

Quiz on Numerics

Exercise 1: Playing with Numbers

Exercise 2: Finding Modulo

Exercise 3: Even or Odd?

Built-in Class: String

Working with Strings String Interpolation Quiz on Strings Exercise 1: Concatenate Substrings Exercise 2: Padding and Justifying Exercise 3: Convert String to Float Exercise 4: Prepend a String Exercise 5: Remove Characters from a String

Built-in Classes: TrueClass, FalseClass, and NilClass

The true, false, and nil Objects

Built-in Class: Symbol

Working with Symbols

Built-in Class: Array

Working with Arrays Things We Can Do with Arrays Quiz on Arrays Exercise 1: Create an Array Exercise 2: Interleaving Exercise 3: Make an Expression Exercise 4: Replace an Element in the Array Exercise 5: Retrieve and Recombine Elements of an Array Exercise 6: Reverse the Array Exercise 7: Delete an Element

Built-in Class: Hash

Working with Hashes Things We Can Do with Hashes Hash Syntax Confusion Quiz on Hashes Exercise 1: Create a Hash Exercise 2: Nested Hash Exercise 3: Flip the Keys and Values

Objects

Objects, Classes, and Methods Objects Are Instances of Classes Objects Have Methods Calling Methods Passing Arguments Listing and Chaining Methods Predicate Methods Bangs Quiz on Objects Exercise 1: Chaining

Methods

Methods Constituents Method Definition Usage Return Values Scopes Combining Methods Printing Things Flow of Execution Quiz on Methods Exercise 1: Greet a Person Exercise 2: Greet Randomly Exercise 3: Convert Miles to Kilometers

Operators are Methods

Arithmetic Operators Logical Operators Comparison Operators Operators Are Methods Quiz on Operators Exercise 1: Check Leap Year

Blocks

What Are Blocks Alternative Block Syntaxes Block Arguments Block Return Values Exercise 1: Extract Even Elements from an Array Inversion of Control Iterators Quiz on Blocks Exercise 2: Even Reversed Exercise 3: Sum the Rows of a Matrix Exercise 4: Print the Output Using Nested Arrays

Mini Project

Get Ready for Some More Drill!

Conditionals

What Are Conditionals?Shorthand Syntax Conditionals Return Values Nothingness and the Truth Quiz on Conditionals Exercise 1: Number of Days in a Month

Coding Challenge: Truthiness and Equivalence

Challenge 1: Checking Truthiness Challenge 2: Equivalent Objects

Mini Project

Lets Run Another Lap with Hashes

Writing Classes

Getting Started with Classes Defining and Instantiating Classes Defining Instance Methods Initializing Objects Instance Variables Class Variables Attribute Readers Attribute Writers State and Behavior Interacting Objects Object Scope and Self Quiz on Classes Exercise 1: Make a Rectangle Class Exercise 2: On Class Methods

Mini Project

The Mailbox Project

Spotlight on Things Unremarked

Top-level Object Escape Sequences Alternative Syntaxes Lots of Other Methods Using the Right Words Terminology: Arguments vs. Parameters Arguments and Parentheses Thought Process Behind Writing a New Method Attention to the Role Played by a Method Quiz on Things Unremarked Exercise 1: Check the Array Equality

Advanced Topics

Using Libraries Modules Private Methods Regular Expressions More on Character Classes (Regex)Quiz on Advanced Topics Exercise 1: Capture the Class Names Exercise 2: Using a Module

Your Toolkit

Text Editor Terminal Interactive Ruby Shell Programming Independently

Appendix: Mailbox Project Prerequisite

A Brief Detour: HTML

Exercise 1: Playing with Numbers

Ready for a time calculation exercise?

We'll cover the following

Problem statement
- Try it yourself

Problem statement

How many hours and minutes are there in the month of December?

Tip: Start writing your code from line 3 below without worrying about the enclosing lines of code.

Try it yourself

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def playing_with_numbers
  hours_in_december = -99, minutes_in_december = -99
  # Start your code here
  return hours_in_december, minutes_in_december
end