Question: I have a full list of timezones in a select menu like so:

```
<option value="Pacific/Kosrae"> Pacific/Kosrae( +11:00 GMT ) </option>
  <option value="Pacific/Kwajalein"> Pacific/Kwajalein( +12:00 GMT ) </option>
  <option value="Pacific/Majuro"> Pacific/Majuro( +12:00 GMT ) </option>
  <option value="Pacific/Marquesas"> Pacific/Marquesas( -09:30 GMT ) </option>
  <option value="Pacific/Midway"> Pacific/Midway( -11:00 GMT ) </option>

```

the list goes on forever.

I want to change each of the options into this format:

```
if($_SESSION['timezone'] == 'Africa/Abidjan') {
echo '<option selected="selected" value="Africa/Abidjan"> Africa/Abidjan( +00:00 GMT ) </option>'; 
} else {
echo '<option value="Africa/Abidjan"> Africa/Abidjan( +00:00 GMT ) </option>';
}

```

How can I use php to avoid having to copy paste and edit each of the options manually??

Answer: 
Store the data in some data structure, and use a loop. For example, using a map from timezone name to offset:

```
$timezones = array(
    'Pacific/Kosrae' => '+11:00',
    'Pacific/Kwajalein' => '+12:00',
    ...
);

foreach($timezones as $name => $offset) {
    echo "<option value=\"$name\"" . ($name == $_SESSION['timezone'] ? " selected" : "") . ">$name( $offset GMT ) </option>\n";
}

```
Ok, imagine you have a variable containing the form above, let's call it `$form` and another variable containing i.e. `'Africa/Abidjan'` - `$timezone.` 

```
$pattern = '/="'.str_replace('/', '\/', $timezone).'"/'; # /="Africa\/Abidjan"/
$replacement = '="'.$timezone.'" selected="selected"'; # ="Africa/Abidjan" selected="selected"
$output_form = preg_replace($pattern, $replacement, $form);

```

Haven't actually tested it, but it should work.