What is $this Variable Vs self in PHP OOPs Tutorial – onlinecode

$this is a pseudo-variable which is a reference to the current object.

$this is mostly used in object oriented code.

$this variable is used to call non-static method, if you are trying to call static method then it will throw the error that means $this variable is not available inside the static method.

Error that you will get while calling a static property or method using $this variable :

Fatal error: Uncaught Error: Using $this when not in object context in .. on line

Note:  Calling non-static methods statically in PHP 7 is deprecated that will generate an E_DEPRECATED warning. So i assume it may be removed in the future to call non-static methods statically.

<?php
class Product {
    public $name='onlinecode';
    public functionaNonStaticMethod(){
        echo$this->name;
    }
}
$p1=newProduct();
$p1->aNonStaticMethod();
?>

<?php
class Product { 
	public $name='onlinecode';
	public function aNonStaticMethod() {
		echo $this->name;
	}
}

$p1 = new Product();

$p1->aNonStaticMethod();

?>

In above example, i have created a Product class with non static method and initialize a object to call aNonStaticMethod to display name property which is declared as public. Here i use $this variable to access public property declared within class.

self keyword

As you notice, this keyword is proceed with $ sign but self keyword is not proceed with any symbol.

With self keyword, you use scope resolution operator.

self keyword with scope resolution operator (::) you can call static method or properties of a class.

self keyword basically refer to current class name within a class.

Example :

<?php
class Product {
    public static$name='onlinecode';
    public functiondisplay(){
        echo self::$name;
    }
}
$p1=newProduct();
$p1->display();
?>

<?php
class Product { 
	public static $name='onlinecode';
	public function display() {
		echo self::$name;
	}
}

$p1 = new Product();

$p1->display();

?>

In above example, you can see i have defined a name property as static and to access static property i use self keyword.