title: Difference between $a == 1 and 1 == $a
body: <p>I have seen multiple examples of such comparison, some other example ( from wordpress core): </p>
  
  <pre><code>if ( '' != $qv['subpost'] )
              $qv['attachment'] = $qv['subpost'];
  </code></pre>
  
  <p>Is code above same as: </p>
  
  <pre><code>if ( $qv['subpost'] != '' )
              $qv['attachment'] = $qv['subpost'];
  </code></pre>
  
  <p>or they are different in functionality? </p>