在这一节中,我们就来看看在PHP中如何创建一个类和对象。
1. 创建类
在PHP中,创建一个类和在C#/Java中基本类似,闲话少说,给大家看个最简单的例子:
class People
{
var $name;
public function GetName()
{
return $this->name;
}
public function SetName($name)
{
$this->name=$name;
}
}
$p=new People();
$p->SetName("kym");
echo($p->GetName());
?>
这里,我们就创建一个People的类,在这里有四个要点说明一下:
第一个是在PHP中,访问属性(或者方法)不是用我们所常用的点运算符(.),而是用->。
第二个是在PHP中,方法需要用function在标识,这点于Javascript很类似。
第三点是当我们声明一个变量时,需要用var,这点也与Javascript非常类似。
第四点是在PHP中,也有着public ,protected,private三个与C#同样的访问修饰符,不再赘述。
在这里,我们发现,我们可以用$p直接访问$name属性,那么我们需要对其进行控制,方法如下:
class People
{
private $name;
public function GetName()
{
return $this->name;
}
public function SetName($name)
{
$this->name=$name;
}
}
这时,我们在外界就无法访问到$name属性了。
还记得我们在上文中提到了可变函数么?在这里我们一样可以用可变函数来访问对象的方法:
class People
{
private $name;
public function GetName()
{
return $this->name;
}
public function SetName($name)
{
$this->name=$name;
}
}
$p=new People();
$get="GetName";
$set="SetName";
$p->$set("kym");
echo($p->$get());
?>
2. 静态方法(属性)
在PHP中声明静态方法(也可称之为类方法)与C#中是十分类似的。
class DataBase
{
public static function CreateConnection()
{
echo("Success");
}
}
DataBase::CreateConnection();
?>
同理,声明静态属性也是一样。
class DataBase
{
static $connectionString="http://127.0.0.1";
public static function CreateConnection()
{
echo("Success");
}
}
echo(DataBase::$connectionString);
DataBase::CreateConnection();
?>
3. 类常量
在C#中,我们用const来标识常量,在PHP中也是一样。
class DataBase
{
const AUTHOR="kym";
static $connectionString="http://127.0.0.1";
public static function CreateConnection()
{
echo("Success");
}
}
echo(DataBase::AUTHOR);
echo(DataBase::$connectionString);
DataBase::CreateConnection();
?>
4. 访问静态变量
我们知道,静态属性(方法)属于类本身,而变量(方法)属于对象本身,而类本身先于对象而存在,那么我们如何来在动态方法中访问静态的变量(方法)呢?在PHP中,为我们提供了self关键字。
class DataBase
{
const AUTHOR="kym";
static $connectionString="http://127.0.0.1";
public static function CreateConnection()
{
echo(self::$connectionString." Success");
}
}
echo(DataBase::AUTHOR);
echo(DataBase::$connectionString);
DataBase::CreateConnection();
?>

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.


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