Introduction

When writing software, we often run into situations where we need to do a specific task in different places within the application that we are building. Without thinking about it, it can be easy to fall into the habit of rewriting the same code over and over again, causing code repetition and making it harder to debug errors when they show up. However, as with all other programming languages, PHP gives you the ability to structure reusable code in what is known as a function, which is also sometimes referred to as a method. These two terms will be used interchangeably throughout this chapter.

Think of a function as a reusable set of instructions or statements. After writing it once, you can call it as many times as you like. Functions bundle logic that should otherwise be kept inseparably together.

Grouping and isolating a set of instructions inside a function comes with a number of benefits. The most obvious one is the option to reuse it: once you have written your...