Detailed explanation of PHP constructor
The content of this article is about the detailed explanation of PHP constructor, which has a certain reference value. Now I share it with everyone. Friends in need can refer to it
// ===Code part 1== =
class Human {
public $name = '李四';
public $gender = '男';
}
$a = new Human();
$b = new Human();
$c = new Human();
echo $a->name,'<br >';
echo $b->name,'<br >';
echo $c->name,'<br >';
// 三个李四
echo $a->gender,'<br >';
echo $b->gender,'<br >';
echo $c->gender,'<br >';
// 三个男
echo '<hr >';
// ===Notes Part 1===
/*
In the class, there is a constructor,
is used to Used to initialize the object,
Using the constructor, you have the opportunity to manipulate the object,
to change its value
Constructor __construct();
When to use the constructor:
Whenever an object is new, the new object will automatically come into play
*/
// Constructor __construct()
// ===Code part 2===
class People {
public function __construct() {
$this->name = '李四'; $this->gender = '女';
} public $name = null; public $gender = null;
}
$a = new People();
$b = new People();
$c = new People();
echo $a->name,'<br >';
echo $b->name,'<br >';
echo $c->name,'<br >';
// 三个李四
echo '<hr >';
// ===Code part 3===
class People2 {
public function __construct($name,$gender) {// 通过在构造函数括号内定义变量，传给构造方法
$this->name = $name; $this->gender = $gender;
}// 构造函数无法重载
/*
public function __construct() {
$this->name = 'nobody';
}
*/
public $name = null;
public $gender = null;
}
$a = new People2('张飞','男');
$b = new People2('空姐','女');
$c = new People2('孙二娘','女');
echo $a->name,'<br >';
echo $b->name,'<br >';
echo $c->name,'<br >';
echo '<hr >';
// Destruction Function __destruct()
// ===Notes Part 2===
/*
Destructor __destruct();
The constructor is When the object is created, the destructor is automatically executed when the object is destroyed. The constructor is automatically executed when the object is destroyed. The constructor is crying when it is born. The destructor is the last words.
1. Explicit destruction, unset, and assignment to null are all acceptable.
2. When PHP executes the code to the last line, all applied memory must be released.
*/
class Human2 {
public $name = null;
public $gender = null;
public function __construct() {
echo '出生了<br >';
}
public function __destruct() {
echo '再见<br >';
}
}$a = new Human2();
$b = new Human2();
$c = new Human2();
$d = new Human2();
unset($a);
$b = false;
$c = null;
echo '<hr >';
Notes on PHP properties and methods
The above is the detailed content of Detailed explanation of PHP constructor. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1664
14
1423
52
1318
25
1269
29
1248
24
Explain JSON Web Tokens (JWT) and their use case in PHP APIs.
Apr 05, 2025 am 12:04 AM
JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,
PHP Program to Count Vowels in a String
Feb 07, 2025 pm 12:12 PM
A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total
Explain late static binding in PHP (static::).
Apr 03, 2025 am 12:04 AM
Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.
What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases?
Apr 03, 2025 am 12:03 AM
What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.
PHP and Python: Comparing Two Popular Programming Languages
Apr 14, 2025 am 12:13 AM
PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.
PHP in Action: Real-World Examples and Applications
Apr 14, 2025 am 12:19 AM
PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
The Enduring Relevance of PHP: Is It Still Alive?
Apr 14, 2025 am 12:12 AM
PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.
