PHP Magic Method: __isset and __unset

From the later version of PHP5, the class will be able to use the Magic method. PHP rules to start with two underscore (__) methods are preserved as a magic method, it is recommended that the function name is best not to start without __, unless it is to reload the existing magic method.

At present, PHP has a magic method has __construct,__destruct,__call,__get,__set,__isset,__unset,__sleep,__wakeup,__tostring,__set_state and __clone.

This paper

Slowly long search night, the moon hanging

__isset ()-a method that automatically executes __isset () if there is no or non-public property when using the Isset () method on a property in a class or in a non-class property

__unset ()-a method that automatically executes __unset () if there is no or non-public property when using the Unset () method on a property in a class or in a non-class property

 public = ' pub ';        $this->protected = ' Pro ';    $this->private = ' pri '; The Public Function __isset ($var) {echo ' Is here through the __isset () method to view the property named '. $var. '    \ n "; The Public Function __unset ($var) {echo ' Is here through the __unset () method to destroy the property named '. $var.    \ n "; }} $exa = new Example;echo '
Var_dump (Isset ($exa->public)), echo "\ n", Var_dump (Isset ($exa->protected)), echo "\ n"; Var_dump (Isset ($exa- >private); echo "\ n"; Var_dump (Isset ($exa->novar)); echo "\ n"; Echo '
 
   '; unset ($exa->public); Var_dump ($exa); echo "\ n"; unset ($exa->protected); echo "\ n"; unset ($exa->private); echo "\ n"; unset ($exa->novar); echo "\ n";
The results are as follows:
BOOL (true) here the __isset () method is used to view the property named Protectedbool (false) here through the __isset () method to view the property named Privatebool (false) here the __isset () method is used to view the property named Novarbool (falseObject (Example) #1 (2) {  ["protected:protected"]=>  String(3"Pro" ["private:private"]=>string (3"pri"} here through the __unset () method to destroy the property named protected here through the __unset () method to destroy the property named Private here through the __unset () method to destroy the property named Novar
                                                
The above describes the PHP magic method: __isset and __unset, including the PHP magic method of content, I hope that the PHP tutorial interested in a friend helpful.
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