Question

<?php
    class test{
        function foo(){
            echo $this->abc;
        }
    }
    $test = new test;
    $test->abc = 'abc';
?>

Remeber that i don’t declare the variable abc, but i want to set $abc to ‘abc’. How to do this
Sorry because this is a dummy question

Answer 1

Actually, this is already working. But it is a bad practice.

Normally you should do something like this:

class test {
    private $abc;

    public function foo() {
        echo $this->abc;
    }

    public function getABC() {
        return $this->abc;
    }

    public function setABC($abc) {
        // You can also add some additionally checks
        $this->abc = $abc;
    }
}

Which makes:

$bar = new test;
$bar->setABC('abc');
$bar->foo();

Remember to make your class attributes ($abc) always private or protected. It’s encapsulation that makes OOP so powerfull.

If you want to use dynamic variable names, so instead of $this->abc you want to set $this->cba you should use the magic methods __set and __get

More about magic methods can be found here:

http://php.net/manual/en/language.oop5.magic.php