title: dateTime return 1 day before week from today
body: <p>How can I return only 1 day before 1 week from today with <code>dateTime</code>?</p>
  
  <p>I did this:</p>
  
  <pre><code>if ($_POST['interval'] == 88) {
  
      $dayNumber = "7";
      $pid = 'P1W';
  }
  
  $now = new DateTime($dayNumber . " days ago");
  $interval = new DateInterval($pid); // 1 Day interval
  $period = new DatePeriod($now, $interval, $dayNumber);
  </code></pre>
  
  <p>This returning day before 1 week and today but + all days between which is not good.</p>