/PHP/When should I use 'self' over '$this'?

When should I use 'self' over '$this'?

Short Answer
Use $this to refer to the current object. Use self to refer to the current class. In other words, use $this->member for non-static members, use self::$member for static members.

Full Answer
Here is an example of correct usage of $this and self for non-static and static member variables:

<?php
class X {
    private $non_static_member = 1;
    private static $static_member = 2;

    function __construct() {
        echo $this->non_static_member . ' '
           . self::$static_member;
    }
}

new X();
?>
Here is an example of incorrect usage of $this and self for non-static and static member variables:

<?php
class X {
    private $non_static_member = 1;
    private static $static_member = 2;

    function __construct() {
        echo self::$non_static_member . ' '
           . $this->static_member;
    }
}

new X();
?>
Here is an example of polymorphism with $this for member functions:

<?php
class X {
    function foo() {
        echo 'X::foo()';
    }

    function bar() {
        $this->foo();
    }
}

class Y extends X {
    function foo() {
        echo 'Y::foo()';
    }
}

$x = new Y();
$x->bar();
?>
Here is an example of suppressing polymorphic behaviour by using self for member functions:

<?php
class X {
    function foo() {
        echo 'X::foo()';
    }

    function bar() {
        self::foo();
    }
}

class Y extends X {
    function foo() {
        echo 'Y::foo()';
    }
}

$x = new Y();
$x->bar();
?>
The idea is that $this->foo() calls the foo() member function of whatever is the exact type of the current object. If the object is of type X, it thus calls X::foo(). If the object is of type Y, it calls Y::foo(). But with self::foo(), X::foo() is always called.

From http://www.phpbuilder.com/board/showthread.php?t=10354489:

By http://board.phpbuilder.com/member.php?145249-laserlight

Source: stackoverflow.com

Similar codes

3 votes225 views3 answers
Num_rows in php
PHP
0 vote166 views1 answer
Laravel print builder
PHP
0 vote168 views2 answers
Concat in where clause laravel query builder
PHP
1 vote232 views1 answer
Php print_r
PHP
0 vote192 views1 answer
Phpmyadmin delete wordpress shortcode
PHP Wordpress
1 vote176 views3 answers
Laravel eloquent to array key value
PHP
0 vote172 views2 answers
Check if user has role twig
PHP
0 vote172 views1 answer
Php datenbank beschreiben
PHP
0 vote191 views1 answer
How get last item in foreach in laravel
PHP Laravel
11 votes219 views6 answers
Route laravel
PHP Laravel