Build multi-dimensional array out of a flat array

drewbee · 05-28-2008, 01:01 AM

Hi All,

I am having some issues doing this. I think the only way to accomplish this is to use a recursive function, however I am failing miserably.

Basically, I need to turn a flat array into a multi-dimensional array.

The flat arrays *values* need to become the new *keys* to the multi-dimensional array.

The array I feed to it can have 1 value in it, up to nth high.
Example:

PHP Code:


			
// Starts out as
$array = array(0 => '0',
                       1 => '15',
                       2 => '32',
                       3 => '18');

// Is turned into
$array = array('0' => 
                                array('15' =>
                                                    array('32' =>
                                                                         array('18' => array()
                                                                                 )
                                                            )
                                        )
                      );

As I said though, my attempts have failed with all kinds of unknown indexes and the like.

PHP Code:


			
    function recursiveBuildArray($array, &$temp)
    {
        if (isset($array['0']))
        {
            $temp[$array['0']] &= array();
            $id = $array['0'];
            unset($array['0']);
            $this->recursiveBuildArray($array[$id], &$temp);
        }
        else
        {
            return false;
        }
    }

Any help on this one?

Salathe · 05-28-2008, 12:00 PM

PHP Code:


			
function make_multi($flat)

{

    $multi = array();

    $temp  =& $multi;

    foreach ($flat as $item)

    {

        $temp[$item] = array();

        $temp =& $temp[$item];

    }

    return $multi;

}



// Quicky test

$test  = array('0', '15', '32', '18');

$multi = make_multi($test);

var_dump($multi);

drewbee · 05-28-2008, 11:38 PM

Awesome, thanks mate!