PHP get first and last day of week

Mon Tue Wed Thu Fri Sat Sun

  $str = date('Y-m-d');
  $iStr = strtotime($str);
  $n = date('N', $iStr);#Mon = 1, Sun = 7
  $d1 = $n - 1; $d2 = 7 - $n;
  # monday in week
  $mon = date('Y-m-d', strtotime("-$d1 days", $iStr));
  # sunday in week
  $sun = date('Y-m-d', strtotime("+$d2 days", $iStr));
  var_dump($mon, $sun);