timezone_name_from_abbr

(PHP 5 >= 5.1.3, PHP 7)

timezone_name_from_abbr — Returns the timezone name from abbreviation

说明

timezone_name_from_abbr ( string $abbr [, int $gmtOffset = -1 [, int $isdst = -1 ]] ) : string

参数

abbr

Time zone abbreviation.

gmtOffset

Offset from GMT in seconds. Defaults to -1 which means that first found time zone corresponding to abbr is returned. Otherwise exact offset is searched and only if not found then the first time zone with any offset is returned.

isdst

Daylight saving time indicator. Defaults to -1, which means that whether the time zone has daylight saving or not is not taken into consideration when searching. If this is set to 1, then the gmtOffset is assumed to be an offset with daylight saving in effect; if 0, then gmtOffset is assumed to be an offset without daylight saving in effect. If abbr doesn't exist then the time zone is searched solely by the gmtOffset and isdst.

返回值

Returns time zone name on success 或者在失败时返回 FALSE.

范例

Example #1 A timezone_name_from_abbr() example

<?php
echo timezone_name_from_abbr("CET") . "\n";
echo timezone_name_from_abbr("", 3600, 0) . "\n";
?>

以上例程的输出类似于：

Europe/Berlin
Europe/Paris

参见

User Contributed Notes

Jon Stovell 24-Sep-2016 05:34
In some cases, timezone_name_from_abbr() may return a "historical" (i.e. deprecated) timezone identifier rather than the current standard one for a given location. For example:
<?php
echo timezone_name_from_abbr('EASST'); // prints "Chile/EasterIsland" instead of "Pacific/Easter"
?>

This means that the returned timezone identifier is not guaranteed to be in the results of timezone_identifiers_list() unless you include the "backwards compatible" timezones.
<?php
var_dump(in_array(timezone_name_from_abbr('EASST'), timezone_identifiers_list())); // (bool)false
var_dump(in_array(timezone_name_from_abbr('EASST'), timezone_identifiers_list(DateTimeZone::ALL_WITH_BC))); // (bool)true
?>
atrauzzi at gmail dot com 16-Mar-2016 12:59
Fun fact: (60*60) * -2 always seems to return null.

Perhaps because there's no timezone that corresponds to UTC -2.
Master Tablu 24-Feb-2009 07:03
Another way to do this is to wrap the function in a class that extends the DateTimeZone class:

<?php

/**
 * Helps with timezones.
 * @link http://us.php.net/manual/en/class.datetimezone.php
 *
 * @package  Date
 */
class Helper_DateTimeZone extends DateTimeZone
{
    /**
     * Converts a timezone hourly offset to its timezone's name.
     * @example $offset = -5, $isDst = 0 <=> return value = 'America/New_York'
     *
     * @param float $offset The timezone's offset in hours.
     *                      Lowest value: -12 (Pacific/Kwajalein)
     *                      Highest value: 14 (Pacific/Kiritimati)
     * @param bool  $isDst  Is the offset for the timezone when it's in daylight
     *                      savings time?
     *
     * @return string The name of the timezone: 'Asia/Tokyo', 'Europe/Paris', ...
     */
    final public static function tzOffsetToName($offset, $isDst = null)
    {
        if ($isDst === null)
        {
            $isDst = date('I');
        }

        $offset *= 3600;
        $zone    = timezone_name_from_abbr('', $offset, $isDst);

        if ($zone === false)
        {
            foreach (timezone_abbreviations_list() as $abbr)
            {
                foreach ($abbr as $city)
                {
                    if ((bool)$city['dst'] === (bool)$isDst &&
                        strlen($city['timezone_id']) > 0    &&
                        $city['offset'] == $offset)
                    {
                        $zone = $city['timezone_id'];
                        break;
                    }
                }

                if ($zone !== false)
                {
                    break;
                }
            }
        }
   
        return $zone;
    }
}
?>

Then you could do something like this:

<?php
$Dtz = new Helper_DateTimeZone(Helper_DateTimeZone::tzOffsetToName(-5));
var_dump($Dtz->getName());

string(16) "America/New_York"
?>
chris at mretc dot net 10-Nov-2008 05:25
timezone_name_from_abbr() sometimes returns FALSE instead of an actual timezone: http://bugs.php.net/44780

It's possible to workaround it for some cases by getting the timezone name from timezone_abbreviations_list(). For example, if you have the GMT offset and want a timezone name:

<?php
/* Takes a GMT offset (in hours) and returns a timezone name */
function tz_offset_to_name($offset)
{
        $offset *= 3600; // convert hour offset to seconds
        $abbrarray = timezone_abbreviations_list();
        foreach ($abbrarray as $abbr)
        {
                foreach ($abbr as $city)
                {
                        if ($city['offset'] == $offset)
                        {
                                return $city['timezone_id'];
                        }
                }
        }

        return FALSE;
}
?>
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