What s the difference between double colon and - arrow in PHP

Question

I know that there are two distinct ways to access methods in PHP.

$response->setParameter('foo', 'bar');

And.

sfConfig::set('foo', 'bar');

But what's the difference between them?

Answer 1

By this symbol, we can call a class method that is static and not dependent on other initialization.

class Test {

    public name;

    public function __construct() {
        this->name = 'Mrinmoy Ghoshal';
    }

    public static function doWrite(name) {
        print 'Hello '.name;
    }

    public function write() {
        print this->name;
    }
}

Here the doWrite() function is not dependent on any other method or variable, and it is a static method. That's why we can call this method by this operator without initializing the object of this class.

Test::doWrite('Mrinmoy'); // Output: Hello Mrinmoy.

But if you want to call the write method in this way, it will generate an error because it is dependent on initialization.

Answer 2

By this symbol, we can call a class method that is static and not dependent on other initialization.

class Test {

    public name;

    public function __construct() {
        this->name = 'Mrinmoy Ghoshal';
    }

    public static function doWrite(name) {
        print 'Hello '.name;
    }

    public function write() {
        print this->name;
    }
}

Here the doWrite() function is not dependent on any other method or variable, and it is a static method. That's why we can call this method by this operator without initializing the object of this class.

Test::doWrite('Mrinmoy'); // Output: Hello Mrinmoy.

But if you want to call the write method in this way, it will generate an error because it is dependent on initialization.