PHP Special Method Set (), Get (), Isset (), and unset ()

The __set () method is used to set the private property value.

The __get () method is used to get the private property value.

The __isset () method is used to detect whether a private property value is set.

The __unset () method is used to delete a private property.

In practice, the properties of a class are often set to private, which makes it cumbersome to access properties. Although it is possible to write access to a property as a method, PHP provides some special methods to facilitate such operations.

__set ()

The __set () method is used to set the value of a private property:

function __set ($property _name, $value) {     $this, $property _name = $value;}

After using the __set () method inside the class, when using the $p 1->name = "Zhang San"; This way, when you set the value of an object's private property, the __set () method is called automatically to set the value of the private property.

__get ()

The __get () method is used to get the private property value:

function __set ($property _name, $value) {     return isset ($this-$property _name)? $this, $property _name:null;}

Example:

 
  ";        $this $property _name = $value;     }    The __get () method is used to get the private attribute    function __get ($property _name) {          echo] automatically calls the __get () method when it obtains the value of the private property directly
";        Return Isset ($this-$property _name)? $this $property _name:null;    }} $p 1=new person ();//The operation that assigns a value directly to a private property automatically calls the __set () method for assignment $p1->name = "Zhang San";//Gets the value of the private property, automatically calls the __get () method, returns the value of the member property echo " My name is: ". $p 1->name;? >

To run the example, output:

The __set () method is automatically called when the private property value is set directly to the private property value when the private property is obtained directly, the __get () method is called automatically. My name is: Zhang San

__isset ()

The __isset () method is used to detect whether a private property value is set.

If the member inside the object is public, you can use the Isset () function directly. If it is a private member property, then you need to add a __isset () method to the class:

Private Function __isset ($property _name) {    return isset ($this, $property _name);}

This automatically calls the __isset () method when the Isset () function is used outside the class to determine whether the private member inside the object is set.

__unset ()

The __unset () method is used to delete a private property.

As with the Isset () function, the unset () function can only delete the public member properties of an object, and the __unset () method is required when you want to delete private member properties inside the object:

Private Function __unset ($property _name) {    unset ($this, $property _name);}

The __set () method is used to set the private property value.

The __get () method is used to get the private property value.

The __isset () method is used to detect whether a private property value is set.

The __unset () method is used to delete a private property.

In practice, the properties of a class are often set to private, which makes it cumbersome to access properties. Although it is possible to write access to a property as a method, PHP provides some special methods to facilitate such operations.

__set ()

The __set () method is used to set the value of a private property:

function __set ($property _name, $value) {     $this, $property _name = $value;}

After using the __set () method inside the class, when using the $p 1->name = "Zhang San"; This way, when you set the value of an object's private property, the __set () method is called automatically to set the value of the private property.

__get ()

The __get () method is used to get the private property value:

function __set ($property _name, $value) {     return isset ($this-$property _name)? $this, $property _name:null;}

Example:

 
  ";        $this $property _name = $value;     }    The __get () method is used to get the private attribute    function __get ($property _name) {          echo] automatically calls the __get () method when it obtains the value of the private property directly
";        Return Isset ($this-$property _name)? $this $property _name:null;    }} $p 1=new person ();//The operation that assigns a value directly to a private property automatically calls the __set () method for assignment $p1->name = "Zhang San";//Gets the value of the private property, automatically calls the __get () method, returns the value of the member property echo " My name is: ". $p 1->name;? >

To run the example, output:

The __set () method is automatically called when the private property value is set directly to the private property value when the private property is obtained directly, the __get () method is called automatically. My name is: Zhang San

__isset ()

The __isset () method is used to detect whether a private property value is set.

If the member inside the object is public, you can use the Isset () function directly. If it is a private member property, then you need to add a __isset () method to the class:

Private Function __isset ($property _name) {    return isset ($this, $property _name);}

This automatically calls the __isset () method when the Isset () function is used outside the class to determine whether the private member inside the object is set.

__unset ()

The __unset () method is used to delete a private property.

As with the Isset () function, the unset () function can only delete the public member properties of an object, and the __unset () method is required when you want to delete private member properties inside the object:

Private Function __unset ($property _name) {    unset ($this, $property _name);}

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