Create a comma-separated string from a single column of an array of objects

Question

I\'m using a foreach loop to echo out some values from my database, I need to strip the last comma from the last loop if that makes sense.

My loop is just simple, as

Answer 1

$value)
{
    $str .= ''.$value['cat_title'].'';
    if($len > $i)
    {
        $str .= ',';
        $i = $i+1;
    }
}
echo $str;
?>