php - Sort multidimensional array alphabetically

Question

How can I sort a array like this alphabetically:

$allowed = array(
  'pre'    => array(),
  'code'   => array(),
  'a'      => array(
                'href'  => array(),
                'title' => array()
              ),
  'strong' => array(),
  'em'     => array(),
);

// sort($allowed); ?

?

Answer 1

Aha! You need uksort();

Comparison of PHP sorting functions. (dam useful)

Edit: Reason is, you seem to want to sort inside arrays as well? AFAIK ksort by itself doesn't do that - it outright ignores the value of the original array.

Edit2: This ought to work (though uses recursion instead of kusort):

function ksort_deep(&$array){
    ksort($array);
    foreach($array as &$value)
        if(is_array($value))
            ksort_deep($value);
}

// example of use:
ksort_deep($allowed);

// see it in action
echo '<pre>'.print_r($allowed,true).'</pre>';

Important: As a side effect of not using uksort() if the same array references to itself, you get an infinite loop. This won't happen in normal cases, but you never know :)