Question

I try to call a member variable of a class from inside a method of the same class.

If I call it directly it doesn’t work, it requires to use the $this. Is there a reason for this? Can’t the class realize that the variable I am calling belongs to it?

Answer 1

The reason is more or less just because that’s how PHP works. It sounds like you are used to Java which automatically uses instance members in the current scope if there is not a local variable that overrides the member in the same scope. PHP does not grant you this liberty:

class x {
    private $y = 'r';

    public function z() {
        $y = 'q';
        echo "$this->y\n"; //r
        echo "$y";         //q
    }
}

In Java, you would still have to use this.y in the above example to print r because the class member name has been overridden locally. Just imagine that PHP’s members are always overridden in methods by void.