PHP Class Constants: Tutorial with Code Examples (2023)

What is a PHP Class Constant? PHP class constant is a value defined within a class and cannot be changed during the execution of the script. They are similar to variables, but unlike variables, their value remains constant throughout the script execution. In object-oriented programming, class constants are used to define data that belongs to a class rather than a specific instance of a class. They offer several advantages, such as better code readability and centralized data management. PHP Class Constant Code Example <?php class Math { public const PI = 3.14159265359; public static function areaOfCircle($radius) { return self::PI * $radius * $radius; } public static function circumferenceOfCircle($radius) { return 2 * self::PI * $radius; } } echo Math::areaOfCircle(5); // Output: 78.539816339744 echo Math::circumferenceOfCircle(5); // Output: 31.4159265358979 ?> Article Highlights Class constants are immutable values that are associated with a specific class in PHP. Class constants are declared using the…

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PHP Dependency Injection Tutorial + 3 Code Examples 2023

Dependency Injection PHP Tutorial Dependency injection is a popular design pattern used in modern programming languages to promote code reusability, maintainability, and testability. It allows developers to manage object dependencies and decouples classes from their dependencies, making them more flexible and easier to manage. This article is part of our larger series on using Object-Oriented Programming (OOP) in PHP. Click here to start from the beginning.  In this article, we will discuss what dependency injection is, how it can be used in PHP, and the different types of dependency injection available. Dependency Injection PHP Code Example <?php require 'vendor/autoload.php'; use DI\ContainerBuilder; // Instantiate container builder $builder = new ContainerBuilder(); // Configure container $builder->addDefinitions([ UserController::class => function ($container) { return new UserController( $container->get(UserService::class) ); }, UserService::class => function ($container) { return new UserService(); }, ]); // Build container $container = $builder->build(); class UserService { public function createUser(array $data) { // validate…

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Object-Oriented PHP Programming Tutorial + 10 Code Examples

How to Use Object-Oriented Programming in PHP the Right Way Object-Oriented PHP programming is a programming paradigm that uses classes and objects to define the logical structure of an application. OOP is a vast topic with many essential concepts, including inheritance, polymorphism, abstraction, and encapsulation. This article gives an overview of these important topics and includes some examples to clarify syntax in PHP. If you want to learn more about each of these topics, then follow us in the object-oriented PHP programming series at FuelingPHP. Table of Contents What is Object-Oriented Programming Object-Oriented Programming vs Procedural Programming Classes Inheritance Polymorphism Abstract Classes Interfaces Fundamentals of Good Web Development What is Object-Oriented PHP Programming? Object-Oriented Programming (OOP) is a popular programming paradigm that relies on classes and objects as reusable building blocks. Contrary to procedural programming, OOP defines a model for a real-world application, including entities as classes and objects from…

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Using Abstract Classes Correctly with PHP Code Examples in 2023

What is an Abstract Class in PHP An abstract class in PHP is a class with at least one not implemented method. You cannot use an abstract class directly but must extend it with a child class. The child classes are supposed to provide an implementation for these abstract methods. Using an Abstract Class in PHP Create an abstract class in PHP by adding the modifier "abstract" before noting the access level. Do the same thing for any methods you want to require child classes to implement. You can see the below for an example. Abstract Class Code Example <?php abstract public class Bird { abstract public function fly() {} public function walk() { // do something concrete here } public class Flamingo extends Bird { public function fly() { // do something here } } But why and what is the purpose of all this? That’s precisely why we…

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Using Interfaces in PHP Correctly with Code Examples in 2023

What is an interface in PHP? Interface in PHP or more generally in Object Oriented Programming (OOP) is an idea of having a higher level of representation or more precisely an abstraction over more specialized and concrete classes. That sounds like a philosophical thing.  Worry not, because we have a lot to say about interfaces and what they are in Object Oriented Programming (OOP). Stay tuned till the end to learn more. What’s with the term ‘interface’? The term ‘interface’ changes meaning in different contexts. Perhaps, that’s a reason why it is often a misunderstood term. So, let’s see the different meanings of this term in different contexts. User Interface / User Experience (UI/UX) Designers use the term interface for visible and interactive elements of an application, more generally called the ‘Frontend’ of an application. In fact, the ‘User Interface’ (UI) is an important aspect of human & machine interactions.…

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How to Use PHP Classes Correctly with Code Examples in 2023

class in php
What is a Class in PHP . A class is a fundamental concept in object oriented programming so the article features a section about PHP OOP basics. If you’re already familiar with OOP concepts you can jump straight to the example following the OOP basics section. However, we recommend staying tuned from beginning to end to gain some really good insights about PHP OOP and especially about the concept of a class in PHP.  Class and Object - PHP OOP Basics A class is a fundamental concept in object-oriented programming. It is a blueprint or a template that defines an entity. The cool thing about a class is that you can create objects based on it. Let’s understand this class and object concept with an analogy. Properties  A master plan (class) forms a baseline for producing various cars in the image above. These cars have a color property that differs.…

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