Iterate over indexed array and group evey two values into associative array

gistfile1.php

<?php

$array = ['string1', 'string2', 'string3'];

$obj = new ArrayObject( $array );
$it = $obj->getIterator();

$new = [];

while($it->valid())
{
	if(!isset($new[$it->current()]))
	{
		$new[$it->current()] = '';
		$holdCurrent = $it->current();
		$it->next();
		$new[$holdCurrent] = $it->current();
		$it->next();
	}
}

var_dump($new);