How to explain 'this' keyword in a best and simple way?

Question

I am using \'this\' keyword for a long time. But when someone asks me to explain it, I am confused that how to explain it. I know that I can use this in a method of class to

Answer 1

Like their name suggests, instance methods operate on instances of a class. How do they know which one to operate on? That's what the this parameter is for.

When you invoke an instance method, you're really invisibly passing in an extra parameter: the object to invoke it on. For example, when you have this:

class Basket {
  public function a() {
    $this-> ...;
    // ...
  }
  // ...
}

and you call $some_basket->a(), behind the scenes you're actually calling something like Basket::a($some_basket). Now a() knows which Basket you want to work with. That special parameter is what this refers to: the current object you're dealing with.