“Notice: Undefined variable”, “Notice: Undefined index”, and “Notice: Undefined offset” using PHP

Question

I\'m running a PHP script and continue to receive errors like:

Notice: Undefined variable: my_variable_name in C:\\wamp\\www\\mypath\\index.php on line 10

Answer 1

If working with classes you need to make sure you reference member variables using $this:

class Person
{
    protected $firstName;
    protected $lastName;

    public function setFullName($first, $last)
    {
        // Correct
        $this->firstName = $first;

        // Incorrect
        $lastName = $last;

        // Incorrect
        $this->$lastName = $last;
    }
}