time - PHP Timezone List

Question

I am looking for a way to generate a list of timezones for display in a <select> Generating a drop down list of timezones with PHP

    $list = DateTimeZone::listAbbreviations();
    $idents = DateTimeZone::listIdentifiers();

    $data = $offset = $added = array();
    foreach ($list as $abbr => $info) {
        foreach ($info as $zone) {
            if ( ! empty($zone['timezone_id'])
                AND
                ! in_array($zone['timezone_id'], $added)
                AND 
                  in_array($zone['timezone_id'], $idents)) {
                $z = new DateTimeZone($zone['timezone_id']);
                $c = new DateTime(null, $z);
                $zone['time'] = $c->format('H:i a');
                $data[] = $zone;
                $offset[] = $z->getOffset($c);
                $added[] = $zone['timezone_id'];
            }
        }
    }

    array_multisort($offset, SORT_ASC, $data);
    $options = array();
    foreach ($data as $key => $row) {
        $options[$row['timezone_id']] = $row['time'] . ' - '
                                        . formatOffset($row['offset']) 
                                        . ' ' . $row['timezone_id'];
    }

    // now you can use $options;

function formatOffset($offset) {
        $hours = $offset / 3600;
        $remainder = $offset % 3600;
        $sign = $hours > 0 ? '+' : '-';
        $hour = (int) abs($hours);
        $minutes = (int) abs($remainder / 60);

        if ($hour == 0 AND $minutes == 0) {
            $sign = ' ';
        }
        return 'GMT' . $sign . str_pad($hour, 2, '0', STR_PAD_LEFT) 
                .':'. str_pad($minutes,2, '0');

}

When I checked my country, the offset was wrong, I am in Asia/Singapore, it should be UTC/GMT +8 http://www.timeanddate.com/worldclock/city.html?n=236 but according to the generated list its +9. Is there some kind of logic error? The time was correct tho

Is there a better way to generate this list? from the same question in the link above,

static $regions = array(
    'Africa' => DateTimeZone::AFRICA,
    'America' => DateTimeZone::AMERICA,
    'Antarctica' => DateTimeZone::ANTARCTICA,
    'Aisa' => DateTimeZone::ASIA,
    'Atlantic' => DateTimeZone::ATLANTIC,
    'Europe' => DateTimeZone::EUROPE,
    'Indian' => DateTimeZone::INDIAN,
    'Pacific' => DateTimeZone::PACIFIC
);
foreach ($regions as $name => $mask) {
    $tzlist[] = DateTimeZone::listIdentifiers($mask);
}

This just gets the identifiers I want a friendly display name eg. UTC+8 Asia/Singapore or something similar. How can I get that?

Answer 1

Take my array of time zones, which I made specially for select element. It is associated array where key is PHP time zone and value is human representation. This is it:

$timezones = array(
    'Pacific/Midway'       => "(GMT-11:00) Midway Island",
    'US/Samoa'             => "(GMT-11:00) Samoa",
    'US/Hawaii'            => "(GMT-10:00) Hawaii",
    'US/Alaska'            => "(GMT-09:00) Alaska",
    'US/Pacific'           => "(GMT-08:00) Pacific Time (US & Canada)",
    'America/Tijuana'      => "(GMT-08:00) Tijuana",
    'US/Arizona'           => "(GMT-07:00) Arizona",
    'US/Mountain'          => "(GMT-07:00) Mountain Time (US & Canada)",
    'America/Chihuahua'    => "(GMT-07:00) Chihuahua",
    'America/Mazatlan'     => "(GMT-07:00) Mazatlan",
    'America/Mexico_City'  => "(GMT-06:00) Mexico City",
    'America/Monterrey'    => "(GMT-06:00) Monterrey",
    'Canada/Saskatchewan'  => "(GMT-06:00) Saskatchewan",
    'US/Central'           => "(GMT-06:00) Central Time (US & Canada)",
    'US/Eastern'           => "(GMT-05:00) Eastern Time (US & Canada)",
    'US/East-Indiana'      => "(GMT-05:00) Indiana (East)",
    'America/Bogota'       => "(GMT-05:00) Bogota",
    'America/Lima'         => "(GMT-05:00) Lima",
    'America/Caracas'      => "(GMT-04:30) Caracas",
    'Canada/Atlantic'      => "(GMT-04:00) Atlantic Time (Canada)",
    'America/La_Paz'       => "(GMT-04:00) La Paz",
    'America/Santiago'     => "(GMT-04:00) Santiago",
    'Canada/Newfoundland'  => "(GMT-03:30) Newfoundland",
    'America/Buenos_Aires' => "(GMT-03:00) Buenos Aires",
    'Greenland'            => "(GMT-03:00) Greenland",
    'Atlantic/Stanley'     => "(GMT-02:00) Stanley",
    'Atlantic/Azores'      => "(GMT-01:00) Azores",
    'Atlantic/Cape_Verde'  => "(GMT-01:00) Cape Verde Is.",
    'Africa/Casablanca'    => "(GMT) Casablanca",
    'Europe/Dublin'        => "(GMT) Dublin",
    'Europe/Lisbon'        => "(GMT) Lisbon",
    'Europe/London'        => "(GMT) London",
    'Africa/Monrovia'      => "(GMT) Monrovia",
    'Europe/Amsterdam'     => "(GMT+01:00) Amsterdam",
    'Europe/Belgrade'      => "(GMT+01:00) Belgrade",
    'Europe/Berlin'        => "(GMT+01:00) Berlin",
    'Europe/Bratislava'    => "(GMT+01:00) Bratislava",
    'Europe/Brussels'      => "(GMT+01:00) Brussels",
    'Europe/Budapest'      => "(GMT+01:00) Budapest",
    'Europe/Copenhagen'    => "(GMT+01:00) Copenhagen",
    'Europe/Ljubljana'     => "(GMT+01:00) Ljubljana",
    'Europe/Madrid'        => "(GMT+01:00) Madrid",
    'Europe/Paris'         => "(GMT+01:00) Paris",
    'Europe/Prague'        => "(GMT+01:00) Prague",
    'Europe/Rome'          => "(GMT+01:00) Rome",
    'Europe/Sarajevo'      => "(GMT+01:00) Sarajevo",
    'Europe/Skopje'        => "(GMT+01:00) Skopje",
    'Europe/Stockholm'     => "(GMT+01:00) Stockholm",
    'Europe/Vienna'        => "(GMT+01:00) Vienna",
    'Europe/Warsaw'        => "(GMT+01:00) Warsaw",
    'Europe/Zagreb'        => "(GMT+01:00) Zagreb",
    'Europe/Athens'        => "(GMT+02:00) Athens",
    'Europe/Bucharest'     => "(GMT+02:00) Bucharest",
    'Africa/Cairo'         => "(GMT+02:00) Cairo",
    'Africa/Harare'        => "(GMT+02:00) Harare",
    'Europe/Helsinki'      => "(GMT+02:00) Helsinki",
    'Europe/Istanbul'      => "(GMT+02:00) Istanbul",
    'Asia/Jerusalem'       => "(GMT+02:00) Jerusalem",
    'Europe/Kiev'          => "(GMT+02:00) Kyiv",
    'Europe/Minsk'         => "(GMT+02:00) Minsk",
    'Europe/Riga'          => "(GMT+02:00) Riga",
    'Europe/Sofia'         => "(GMT+02:00) Sofia",
    'Europe/Tallinn'       => "(GMT+02:00) Tallinn",
    'Europe/Vilnius'       => "(GMT+02:00) Vilnius",
    'Asia/Baghdad'         => "(GMT+03:00) Baghdad",
    'Asia/Kuwait'          => "(GMT+03:00) Kuwait",
    'Africa/Nairobi'       => "(GMT+03:00) Nairobi",
    'Asia/Riyadh'          => "(GMT+03:00) Riyadh",
    'Europe/Moscow'        => "(GMT+03:00) Moscow",
    'Asia/Tehran'          => "(GMT+03:30) Tehran",
    'Asia/Baku'            => "(GMT+04:00) Baku",
    'Europe/Volgograd'     => "(GMT+04:00) Volgograd",
    'Asia/Muscat'          => "(GMT+04:00) Muscat",
    'Asia/Tbilisi'         => "(GMT+04:00) Tbilisi",
    'Asia/Yerevan'         => "(GMT+04:00) Yerevan",
    'Asia/Kabul'           => "(GMT+04:30) Kabul",
    'Asia/Karachi'         => "(GMT+05:00) Karachi",
    'Asia/Tashkent'        => "(GMT+05:00) Tashkent",
    'Asia/Kolkata'         => "(GMT+05:30) Kolkata",
    'Asia/Kathmandu'       => "(GMT+05:45) Kathmandu",
    'Asia/Yekaterinburg'   => "(GMT+06:00) Ekaterinburg",
    'Asia/Almaty'          => "(GMT+06:00) Almaty",
    'Asia/Dhaka'           => "(GMT+06:00) Dhaka",
    'Asia/Novosibirsk'     => "(GMT+07:00) Novosibirsk",
    'Asia/Bangkok'         => "(GMT+07:00) Bangkok",
    'Asia/Jakarta'         => "(GMT+07:00) Jakarta",
    'Asia/Krasnoyarsk'     => "(GMT+08:00) Krasnoyarsk",
    'Asia/Chongqing'       => "(GMT+08:00) Chongqing",
    'Asia/Hong_Kong'       => "(GMT+08:00) Hong Kong",
    'Asia/Kuala_Lumpur'    => "(GMT+08:00) Kuala Lumpur",
    'Australia/Perth'      => "(GMT+08:00) Perth",
    'Asia/Singapore'       => "(GMT+08:00) Singapore",
    'Asia/Taipei'          => "(GMT+08:00) Taipei",
    'Asia/Ulaanbaatar'     => "(GMT+08:00) Ulaan Bataar",
    'Asia/Urumqi'          => "(GMT+08:00) Urumqi",
    'Asia/Irkutsk'         => "(GMT+09:00) Irkutsk",
    'Asia/Seoul'           => "(GMT+09:00) Seoul",
    'Asia/Tokyo'           => "(GMT+09:00) Tokyo",
    'Australia/Adelaide'   => "(GMT+09:30) Adelaide",
    'Australia/Darwin'     => "(GMT+09:30) Darwin",
    'Asia/Yakutsk'         => "(GMT+10:00) Yakutsk",
    'Australia/Brisbane'   => "(GMT+10:00) Brisbane",
    'Australia/Canberra'   => "(GMT+10:00) Canberra",
    'Pacific/Guam'         => "(GMT+10:00) Guam",
    'Australia/Hobart'     => "(GMT+10:00) Hobart",
    'Australia/Melbourne'  => "(GMT+10:00) Melbourne",
    'Pacific/Port_Moresby' => "(GMT+10:00) Port Moresby",
    'Australia/Sydney'     => "(GMT+10:00) Sydney",
    'Asia/Vladivostok'     => "(GMT+11:00) Vladivostok",
    'Asia/Magadan'         => "(GMT+12:00) Magadan",
    'Pacific/Auckland'     => "(GMT+12:00) Auckland",
    'Pacific/Fiji'         => "(GMT+12:00) Fiji",
);