#### Overview of this book

Ruby is a powerful, general-purpose programming language that can be applied to any task. Whether you are an experienced developer who wants to learn a new language or you are new to programming, this book is your comprehensive Ruby coding guide. Starting with the foundational principles, such as syntax, and scaling up to advanced topics such as big data analysis, this book will give you all of the tools you need to be a professional Ruby developer. A few of the key topics are: object-oriented programming, built-in Ruby methods, core programming skills, and an introduction to the Ruby on Rails and Sinatra web frameworks. You will also build 10 practical Ruby programs. Created by an experienced Ruby developer, this book has been written to ensure it focuses on the skills you will need to be a professional Ruby developer. After you have read this book, you will be ready to start building real-world Ruby projects.
Preface
Free Chapter
Introduction to the Ruby Programming Language
Ruby Variables
Ruby Strings
Working with Numbers in Ruby
Ruby Iterators and Loops
Ruby Collections
Ruby Conditionals
Working with the Filesystem in Ruby
Error Handling in Ruby
Regular Expressions in Ruby
Searching with grep in Ruby
Ruby Gems
Ruby Web Frameworks
Working with APIs in Ruby
Machine Learning

# Arithmetic order of operations

When using arithmetic operators, it's important to understand the order of operations, as the compiler uses a specific format to determine this order.

So, what does this order mean for a problem/equation?

Let's say that we need to run an equation with all these operators, but in a different order. For example: 5 + 15 * 20 - 2 / 6 ** 3 - (3 + 1).

In the preceding problem, we have all the six operations included. If we run this code, it gives a value of 301.

To break it down, the compiler first looked for the parentheses, so it computed the value (3+1), which is 4. Then, it handled the exponent 6**3, which is 216. Next is multiplication, so 15 * 20 is 300. Now, for division, 2/216 will be equal to 0 (it's not really zero, but we'll discuss this in the next section). Next, it focuses on addition, 5 + 300 which equals 305. And lastly...