This article mainly introduces PHP object-oriented classes and instantiated objects, which has a certain reference value. Now I share it with everyone. Friends in need can refer to it

Class

Declaration

[修饰符] class 类名
{
    [属性]
    [方法]
}

Notes:

1) The class name follows the camel case naming convention that starts with uppercase

private     私有

protected   保护

public      公共    

var         被视为public  (不建议使用)

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// 1.声明类
class Dog
{
    // 2.定义属性
    public $name = '旺财';
    public $sex = null;


    // 3.定义方法
    public function bark()
    {
        echo '汪汪~';
    }
}

// 4.实例化
$d1 = new Dog();

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Instantiated object

-> , to access non-static properties | methods.

Example

// 声明类
class Dog
{
    // 定义属性
    public $name = '旺财';
    public $sex = null;


    // 定义方法
    public function bark()
    {
        echo '汪汪~';
    }
}

// 实例化
$d1 = new Dog();

// 使用属性和方法
echo $d1 -> name;
echo &#39;<br/>&#39;;
echo $d1 -> bark();

$this .

$this represents the object being used.

Example:

// 声明类
class Dog
{
    // 定义属性
    public $name = '旺财';
    public $sex = null;

    public function intruduce()
    {
        echo '我的名字是'.$this->name;
    }
}

Simple type, both sides of the assignment, mutually independent.

composite type, the identifier of the object is stored in the transfer assignment, so the changes are consistent .

Simple type example:

$a = 'abc';

// 传递赋值
$b = $a;

// 更改a的值
$a = 'qq';

var_dump($a);   // qq
var_dump($b);   // abc

Composite type example:

class MyClass
{
    public $str = 'abc';
}

// $a 存的是对象的标识符
$a = new MyClass();

// 传递赋值  相当于把标识符赋值给了$b
$b = $a;

var_dump($a);    // abc
var_dump($b);    // abc

// 更改a对象str属性的值
$a -> str ='111';

// $a和$b存的都是标识符
var_dump($a);    // 111
var_dump($b);    // 111


// 更改a本身的值
$a = 123;

var_dump($a);    // 123
var_dump($b);    // 111   对象标识符

Example:

$a = 'abc';

// 引用赋值
$c = &$a;

var_dump($a);   // qq
var_dump($c);   // qq

php basic object-oriented concepts

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