


Notes after reading the php manual 2015-03-19 version, php2015-03-19_PHP tutorial
Remarks after reading the php manual 2015-03-19 version, php2015-03-19
Classes and objects->Basic concepts:
1, #### ########################
::class
Since PHP 5.5, the keyword class can also be used for class name resolution. Using ClassName::class you can get a string containing the fully qualified name of the class ClassName. This is especially useful for classes that use namespaces.
Example #7 Class name resolution as stated in the docs is:
namespace NS {
class ClassName {
}
echo ClassName::class;
}
?>
The above routine will output:
NSClassName
2,################ ############
Just to be clear: the correct way of validating a classname, as stated in the docs is:
$valid = preg_match('/^[a-zA -Z_x7f-xff][a-zA-Z0-9_x7f-xff]*$/', $className);
3,################# ############
Variables in attributes can be initialized, but the initialized value must be a constant. The constant here means that the PHP script can get its value during the compilation phase without relying on Only runtime information can be evaluated
PHP 5.3.0 adds support for Nowdoc declaration class attributes; heredoc without variables is also possible, but it is wrong to include variables.
new static() will follow the inheritance relationship, new is the subclass
new self() will not be inherited, new is the class where the word self is located
###
As of PHP 5.6 you can finally define constant using math expressions, like this one:
class MyTimer {
const SEC_PER_DAY = 60 * 60 * 24;
}
?>
###
Since PHP 5.3.3, in the namespace, methods with the same name as the class name are no longer as a constructor. This change does not affect classes that are not in the namespace.
namespace Foo;
class Bar {
public $a;
public function Bar() {
$this->a = 'to here';
}
public function getA(){
return $this->a;
}
}
$bar = new Bar();
echo $bar- >getA(); //Empty; remove the namespace and output to here;
###
Since PHP 5.3.0, classes can be referenced through variables. The value of this variable cannot be keywords (such as self, parent and static).
With organization:
self, parent and static
public (public), protected (protected) or private (private)

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Dreamweaver Mac version
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

WebStorm Mac version
Useful JavaScript development tools