php - function to set var if it key exists in array, otherwise set to default

So I've got a class that I'd like to have it just set defaults if they're not passed in. For example, I can pass it an array called $options.

function new_score($options)
{

}

Then I'd like to have a different function that I can set a var to a default if a key with that var's name doesn't exist in the $options array;

The function definiti开发者_JAVA百科on could look like this:

function _set(&$key, $options, $default)
{
}

I know there's array_key_exists(), and I guess I'm sort of looking for a way to access the variables name.

For example:

$apple = 'orange';

How can I get the string 'apple', so I can look for that key? I know I could take the function _set() and have it look for $key, $var, $options, and $default, but I'd rather abstract it further.

---

function method($options)
{
  //First, set an array of defaults:
  $defaults = array( "something" => "default value",
                     "something_else" => "another default");

  //Second, merge the defaults with the $options received:
  $options = array_merge($defaults, $options);

  //Now you have an array with the received values or defaults if value not received.
  echo($options["something"]);

  //If you wish, you can import variables into local scope with "extract()"
  //but it's better not to do this...
  extract($options);
  echo($something);
}

References:

http://ar.php.net/manual/en/function.array-merge.php

http://ar.php.net/manual/en/function.extract.php

---

there's two ways of doing this:

One at a time with the ternary operator:

$key = isset($array['foo']) ? $array['foo'] : 'default';

Or, as an array as a whole:

$defaults = array('foo' => 'bar', 'other' => 'default value');
$array = $array + $defaults;

---

How about this:

class Configurable
{
 private static $defaults = array (
  'propertyOne'=>'defaultOne',
  'propertyTwo'=>'defaultTwo'
 );

 private $options;

 public function __construct ($options)
 {
  $this->options = array_merge (self::$defaults, $options);
 } 
}

From the documentation for array_merge:

If the input arrays have the same string keys, then the later value for that key will overwrite the previous one.