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Learn how to use PHP to create object-oriented programs and apps!

Object-oriented programming (OOP) is a programming paradigm that uses objects to represent and manipulate data.

In PHP, OOP helps to create reusable code, increase code maintainability and reduce code duplication.

If you’re a PHP developer, you should learn OOP to write better code and improve your skills.

Getting started

OOP is suitable for PHP developers who want to write reusable and maintainable code.

It’s also useful for developers who want to work with PHP frameworks like Laravel, Symfony, and CodeIgniter.

How to

  1. Create a class: A class is a blueprint that defines the properties and methods of an object. Use the class keyword to create a class.
  2. Create an object: An object is an instance of a class. Use the new keyword to create an object.
  3. Define properties: Properties are the characteristics of an object. Use the public, private, or protected keywords to define properties.
  4. Define methods: Methods are the actions that an object can perform. Use the public, private, or protected keywords to define methods.
  5. Inheritance: Inheritance allows a class to inherit properties and methods from another class. Use the extends keyword to inherit a class.
  6. Polymorphism: Polymorphism allows an object to take on many forms. Use the abstract and interface keywords to implement polymorphism.
  7. Encapsulation: Encapsulation is the practice of hiding the internal workings of an object from the outside world. Use the public, private, or protected keywords to encapsulate properties and methods.

Best practices

  • Use meaningful class and method names.
  • Use the public, private, or protected keywords to control access to properties and methods.
  • Use inheritance and polymorphism to reduce code duplication.
  • Use encapsulation to protect the internal workings of an object.

Examples

Let’s say you’re building a website for a car dealership.

You want to create a class that represents a car and its properties.

Here’s how you could do it:


class Car {
  public $make;
  public $model;
  public $year;
  
  public function __construct($make, $model, $year) {
    $this->make = $make;
    $this->model = $model;
    $this->year = $year;
  }
  
  public function getMake() {
    return $this->make;
  }
  
  public function getModel() {
    return $this->model;
  }
  
  public function getYear() {
    return $this->year;
  }
}

$car = new Car("Honda", "Civic", 2021);
echo $car->getMake(); // Output: Honda
echo $car->getModel(); // Output: Civic
echo $car->getYear(); // Output: 2021

In this example, we created a Car class with properties for make, model, and year.

We also defined methods to get the values of these properties.

Finally, we created an object of the Car class and called its methods to get the property values.
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