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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: Float or Integer Exercise 1: Playing with Numbers Exercise 2: Finding Modulo Exercise 3: Even or Odd?

Built-in Class: String

Working with Strings String Interpolation Quick Quiz Exercise 1: Concatenate Substrings Exercise 2: Padding & Justifying Exercise 3: Convert String to Float Exercise 4: Prepend a String Exercise 5: Remove Characters from 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 You Can Do with Arrays Quick Quiz 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 You Can Do with Hashes Hash Syntax Confusion Quiz: Guess the Answers 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 Predicates Bangs Quick Quiz on Objects Exercise 1: Chaining

Methods

Methods Constituents Method Definition Usage Return Values Scopes Combining Methods Printing Things Flow of Execution Exercise 1: Greet a Person Exercise 2: Greet Randomly Exercise 3: Convert Miles to Kilometers Exercise 4: Check Leap Year

Operators are Methods

Arithmetical Operators

Logical Operators

Comparison Operators

Operators are Methods

Quick Quiz on Operators

Blocks

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

Project

Get Ready for some more Drill!

Conditionals

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

Coding Challenge: Truthiness and Equivalence

Challenge 1: Checking Truthiness Challenge 2: Equivalent Objects

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 Quick Quiz on Classes Exercise 1: Make a Rectangle Class Exercise 2: On Class Methods

Project

Mini project 1

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 Quick Quiz Exercise 1: Check the Array Equality

Advanced Topics

Using Libraries Modules Private Methods Regular Expressions More on Character Classes (Regex)Quick Quiz 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

Conclusion

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Comparison Operators

Comparison Operators

Learn about Ruby’s comparison operators.

In order to compare things, Ruby has a bunch of comparison operators.

The == operator

The == operator returns true if both objects are considered the same.

For example, 1 == 1 * 1 returns true because the numbers on both sides represent the same value. The expression "A" == "A" also returns true ...