How to match new variables against default variables in a class?

In jQuery there is $.extend() function. That basically works like matching default settings with input settings. Well, I want to use similar technique in PHP, but it seems, that there is no similar function. So I'm wondering: Is there a similar function as .extend(), but in PHP? If not then, what alternatives are there?

This is an example class and how I get this effect currently. I also added a comment, how I would wish to do this:

class TestClass {
    // These are the default settings:
    var $settings = array(
        'show' => 10,
        'phrase' => 'Miley rocks!',
        'by' => 'Kalle H. Väravas',
        'version' => '1.0'
    );
    function __construct ($input_settings) {
        // This is how I would wish to do this:
        // $this->settings = extend($this->settings, $input_settings);

        // This is what I want to get rid of:
        $this->settings['show'] = empty($input_settings['show']) ? $this->settings['show'] : $input_settings['show'];
        $this->settings['phrase'] = empty($input_se开发者_Go百科ttings['phrase']) ? $this->settings['phrase'] : $input_settings['phrase'];
        $this->settings['by'] = empty($input_settings['by']) ? $this->settings['by'] : $input_settings['by'];
        $this->settings['version'] = empty($input_settings['version']) ? $this->settings['version'] : $input_settings['version'];

        // Obviously I cannot do anything neat or dynamical with $input_settings['totally_new'] :/
    }
    function Display () {
        // For simplifying purposes, lets use Display and not print_r the settings from construct
        return $this->settings;
    }
}

$new_settings = array(
    'show' => 30,
    'by' => 'Your name',
    'totally_new' => 'setting'
);

$TC = new TestClass($new_settings);

echo '<pre>'; print_r($TC->Display()); echo '</pre>';

If you notice, that there is a totally new setting: $new_settings['totally_new']. That should just get included inside the array as $this->settings['totally_new']. PS: Above code outputs this.

---

Try to use array_merge php function. Code:

array_merge($this->settings, $input_settings);