title: PHP set date('w') function return Sunday as 7, instead of 0
body: <p>From official manual , the <code>date ('w')</code> shows the current date as </p>
  
  <pre><code>0 = Sunday
  1 = Monday
  
  .....
  
  6 = Saturday
  </code></pre>
  
  <p>The problem is , without any further modification , are there any way (eg. set parameter?) to specific the Sunday as 7 instead of 0 ? thanks</p>