Php Magic Method __isset, __unset use instance _python

__isset () – Automatically executes the __isset () method when the Isset () method is used for attributes in a class or in a non-class property, if there are no or no public properties

__unset ()-method for automatically executing __unset () when a unset () method is used for attributes in a class or in a class other than a public attribute

Copy Code code as follows:

<?php
/**
* Examples of __isset () and __unset () for magic methods in classes
*/

Class Example {
Public $public;
protected $protected;
Private $private;

Public Function __construct () {
$this->public = ' pub ';
$this->protected = ' Pro ';
$this->private = ' pri ';
}

Public Function __isset ($var) {
Echo ' Here through the __isset () method to view the property name '. $var. ' \ n ";
}

Public Function __unset ($var) {
Echo ' Here through the __unset () method to destroy the property name '. $var. ' \ n ";
}
}

$exa = new Example;

Echo ' <pre> ';
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, view the property name protected by the __isset () method

BOOL (FALSE)

Here, view the property name private by the __isset () method

BOOL (FALSE)

Here, view the property name Novar by the __isset () method

BOOL (FALSE)

Copy Code code as follows:

Object (Example) #1 (2) {
["Protected:protected"]=>
String (3) "Pro"
["Private:private"]=>
String (3) "PRI"
}

Here the __unset () method is used to destroy the property name protected

This is done using the __unset () method to destroy the property name private

Here the __unset () method is used to destroy the property name Novar