Either serialize:
$postvalue=array("a","b","c");
<input type="hidden" name="result" value="<?php echo serialize($postvalue); ?>">
on receive: unserialize($_POST['result'])
Or implode:
$postvalue=array("a","b","c");
<input type="hidden" name="result" value="<?php echo implode(',', $postvalue); ?>">
On receive: explode(',', $_POST['result'])