Detailed explanation of php magic method, detailed explanation of php magic
From PHP 5 and later, classes in PHP can use magic methods. It stipulates that methods starting with two underscores (__) are reserved as magic methods, so it is recommended that function names do not start with __ unless it is to overload an existing magic method. PHP reserves all class methods starting with _ _ (two underscores) as magic methods.
__toString() and __invoke()
public string __toString (void): This method will be automatically called when the object is used as a string. This method must return a string
Copy code The code is as follows:
class Magic{
Public function __tostring(){
return "hello world!";
}
}
$obj = new Magic();
echo $obj;//hello world!
?>
__invoke(): This method will be automatically called when the object is called as a method.
Copy code The code is as follows:
class Magic{
Public function __tostring(){
return "hello world!";
}
public function __invoke($x){
echo "__invoke called with param ".$x."n";
}
}
$obj = new Magic();
$obj(10);//__invoke called with param 10
?>
__call() and __callStatic()
__call(): When the object accesses a method name that does not exist, the __call() method will be automatically called
__callStatic(): When the object accesses a non-existent static method name, the __callStatic() method will be automatically called
Through these two methods, calls with the same method name can be implemented corresponding to different methods
Copy code The code is as follows:
class Magic{
//The `$name` parameter is the name of the method to be called. `$arguments` parameter is an enumeration array,
//Contains the parameters to be passed to the method `$name`.
public function __call($name,$arguments){
//implode() function combines array elements into a string. implode(separator,array)
echo "Calling " . $name ." with param: ".implode(", ",$arguments)."n";
}
}
$obj = new Magic();
$obj->run("para1","para2");//obj calls the run method, output: Calling run with param: para1, para2
?>
__get() and __set()
When assigning values to inaccessible properties, __set() will be called
When reading the value of an inaccessible attribute, __get() will be called
Copy code The code is as follows:
class Magic{
//There must be static keyword before function
Public function __get($name){
return "Getting the property " . $name;
}
}
$obj = new Magic();
echo $obj->className."n";//Getting the property className
?>
When reading the value of an inaccessible attribute, __get() will be called
Copy code The code is as follows:
class Magic{
public function __set($name,$value){
echo "Setting the property " . $name ."to value ". $value ."n";
}
}
$obj = new Magic();
$obj->className = 'MagicClass';//Setting the property classNameto value MagicClass
?>
__isset() and __unset()
When isset() or empty() is called on an inaccessible property, __isset() will be called
When unset() is called on an inaccessible property, __unset() will be called
Copy code The code is as follows:
class Magic{
Public function __isset($name){
echo "__isset invokedn";
return true;
}
}
$obj = new Magic();
echo '$obj->className is set?'.isset($obj->className)."n";//__isset invoked $obj->className is set?1
?>
The above is the introduction and examples of 8 PHP object-oriented magic methods. I hope it will be helpful to everyone
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