PHP重置while（）循环

Question

I am using the following which basically prints a dropdown box showing all hours with 30 minute increments:

$start = '12:00AM';
$end = '11:59PM';
$interval = '+30 minutes';

$start_str = strtotime($start);
$end_str = strtotime($end);
$now_str = $start_str;

echo '<select name="doors_open">';

while($now_str <= $end_str){
    echo '<option value="' . date('h:i A', $now_str) . '">' . date('h:i A', $now_str) . '</option>';
    $now_str = strtotime($interval, $now_str);
}

echo '</select>';

BUT, i want to do it twice for another field further down the page... question is, how do I reset the loop?

Here's what I've tried but doesn't work:

echo '<select name="event_start">';

reset($now_str);
reset($end_str);
while($now_str <= $end_str){
    echo '<option value="' . date('h:i A', $now_str) . '">' . date('h:i A', $now_str) . '</option>';
    $now_str = strtotime($interval, $now_str);
}

echo '</select>';

Answer 1

reset() resets the internal cursor of an array. That's a totally different thing than you want to achieve.

You can of course simply duplicate the code, but this neither good code design nor DRY.

The best you can do is to put the whole HTML generation into a helper function:

function genSelect($selectName, $start, $end, $interval) {
  $str = "<select name='$selectName'>";

  $start_str = strtotime($start);
  $end_str = strtotime($end);
  $now_str = $start_str;


  while($now_str <= $end_str){
    $str .= '<option value="' . date('h:i A', $now_str) . '">' . date('h:i A', $now_str) . '</option>';
    $now_str = strtotime($interval, $now_str);
  }

  $str .= '</select>';
  return $str;
}

Then, you can call it as often as you want:

echo genSelect('doors_open', '12:00AM', '11:59PM', '+30 minutes');

You may also consider caching the result:

$doorsOpenHtml = genSelect('doors_open', '12:00AM', '11:59PM', '+30 minutes');