php if empty 2 varaibles for Drupal
I am working in a Drupal template. I want to know if two variables exist, and if they do not then do or show something else. I know how to do this for only one variable, but what is the correct syntax to look for two? My code is below. 

    <?php if (!empty($right) && !empty($left)): ?>
        <div id="content-main">
       <?php endif; ?>

I also tried it this way.

    <?php if (!empty($right)&&($left)): ?>
        <div id="content-main">
       <?php endif; ?> 

and this way.

    <?php if (!isset($right)&&($left)): ?>
        <div id="content-main">
       <?php endif; ?>

None of them work
php if empty 2 varaibles for Drupal
===

I am working in a Drupal template. I want to know if two variables exist, and if they do not then do or show something else. I know how to do this for only one variable, but what is the correct syntax to look for two? My code is below. 

    <?php if (!empty($right) && !empty($left)): ?>
        <div id="content-main">
       <?php endif; ?>

I also tried it this way.

    <?php if (!empty($right)&&($left)): ?>
        <div id="content-main">
       <?php endif; ?> 

and this way.

    <?php if (!isset($right)&&($left)): ?>
        <div id="content-main">
       <?php endif; ?>

None of them work