Sub-namespaces in PHP - Mini Project: Build & Apply

Using Sub-namespaces in PHP

📖 Scenario: You are organizing a PHP project for a small library system. To keep the code clean and easy to manage, you want to use sub-namespaces to separate different parts of the system.

🎯 Goal: Create a PHP script that defines a main namespace and a sub-namespace. Then, create a class inside the sub-namespace and use it in the main script.

📋 What You'll Learn

Create a main namespace called Library

Create a sub-namespace inside Library called Books

Define a class called Book inside the Library\Books namespace

Create an instance of the Book class and print a message using a method from that class

💡 Why This Matters

🌍 Real World

Organizing code in large PHP projects by grouping related classes into sub-namespaces helps keep the code clean and easy to maintain.

💼 Career

Understanding namespaces and sub-namespaces is important for working on professional PHP projects, frameworks, and libraries.

1

Create the main namespace and sub-namespace with a class

Write PHP code to create a namespace called Library\Books. Inside it, define a class called Book with a public method getTitle() that returns the string 'PHP Basics'.

PHP

<?php

// Define namespace Library\Books and class Book with method getTitle()
// Your code here

Need a hint?

Use the namespace keyword followed by Library\Books. Then define the class Book with the method getTitle() returning the exact string.

2

Create a variable to hold the full class name

Add a variable called bookClass and set it to the string 'Library\\Books\\Book' (note the double backslashes).

PHP

<?php

namespace Library\Books;

class Book {
    public function getTitle() {
        return 'PHP Basics';
    }
}

// Create a variable bookClass with the full class name
// Your code here

Need a hint?

Remember to escape backslashes in PHP strings by using double backslashes.

3

Create an instance of the Book class using the variable

Use the variable $bookClass to create a new instance called $book of the Book class.

PHP

<?php

namespace Library\Books;

class Book {
    public function getTitle() {
        return 'PHP Basics';
    }
}

$bookClass = 'Library\\Books\\Book';

// Create an instance $book of the class stored in $bookClass
// Your code here

Need a hint?

Use the variable class name syntax: new $bookClass().

4

Print the book title using the getTitle() method

Write a print statement to display the result of calling getTitle() on the $book object.

PHP

<?php

namespace Library\Books;

class Book {
    public function getTitle() {
        return 'PHP Basics';
    }
}

$bookClass = 'Library\\Books\\Book';

$book = new $bookClass();

// Print the title of the book using getTitle()
// Your code here

Need a hint?

Use print($book->getTitle()); to show the book title.