Get the Olson TZ name for the local timezone?
I think best bet is to go thru all pytz timezones and check which one matches local timezone, each pytz timezone object contains info about utcoffset and tzname like CDT, EST, same info about local time can be obtained from time.timezone/altzone and time.tzname, and I think that is enough to correctly match local timezone in pytz database e.g.
import time
import pytz
import datetime
local_names = []
if time.daylight:
local_offset = time.altzone
localtz = time.tzname[1]
else:
local_offset = time.timezone
localtz = time.tzname[0]
local_offset = datetime.timedelta(seconds=-local_offset)
for name in pytz.all_timezones:
timezone = pytz.timezone(name)
if not hasattr(timezone, '_tzinfos'):
continue#skip, if some timezone doesn't have info
# go thru tzinfo and see if short name like EDT and offset matches
for (utcoffset, daylight, tzname), _ in timezone._tzinfos.iteritems():
if utcoffset == local_offset and tzname == localtz:
local_names.append(name)
print local_names
output:
['America/Atikokan', 'America/Bahia_Banderas',
'America/Bahia_Banderas', 'America/Belize', 'America/Cambridge_Bay',
'America/Cancun', 'America/Chicago', 'America/Chihuahua',
'America/Coral_Harbour', 'America/Costa_Rica', 'America/El_Salvador',
'America/Fort_Wayne', 'America/Guatemala',
'America/Indiana/Indianapolis', 'America/Indiana/Knox',
'America/Indiana/Marengo', 'America/Indiana/Marengo',
'America/Indiana/Petersburg', 'America/Indiana/Tell_City',
'America/Indiana/Vevay', 'America/Indiana/Vincennes',
'America/Indiana/Winamac', 'America/Indianapolis', 'America/Iqaluit',
'America/Kentucky/Louisville', 'America/Kentucky/Louisville',
'America/Kentucky/Monticello', 'America/Knox_IN',
'America/Louisville', 'America/Louisville', 'America/Managua',
'America/Matamoros', 'America/Menominee', 'America/Merida',
'America/Mexico_City', 'America/Monterrey',
'America/North_Dakota/Beulah', 'America/North_Dakota/Center',
'America/North_Dakota/New_Salem', 'America/Ojinaga',
'America/Pangnirtung', 'America/Rainy_River', 'America/Rankin_Inlet',
'America/Resolute', 'America/Resolute', 'America/Tegucigalpa',
'America/Winnipeg', 'CST6CDT', 'Canada/Central', 'Mexico/General',
'US/Central', 'US/East-Indiana', 'US/Indiana-Starke']
In production you can create such a mapping beforehand and save it instead of iterating always.
Testing script after changing timezone:
$ export TZ='Australia/Sydney'
$ python get_tz_names.py
['Antarctica/Macquarie', 'Australia/ACT', 'Australia/Brisbane',
'Australia/Canberra', 'Australia/Currie', 'Australia/Hobart',
'Australia/Lindeman', 'Australia/Melbourne', 'Australia/NSW',
'Australia/Queensland', 'Australia/Sydney', 'Australia/Tasmania',
'Australia/Victoria']
pytz: return Olson Timezone name from only a GMT Offset
UTC offset by itself may be ambiguous (it may correspond to several timezones that may have different rules in some time period):
#!/usr/bin/env python
from datetime import datetime, timedelta
import pytz # $ pip install pytz
input_utc_offset = timedelta(hours=-4)
timezone_ids = set()
now = datetime.now(pytz.utc) #XXX: use date that corresponds to input_utc_offset instead!
for tz in map(pytz.timezone, pytz.all_timezones_set):
dt = now.astimezone(tz)
tzinfos = getattr(tz, '_tzinfos',
[(dt.tzname(), dt.dst(), dt.utcoffset())])
if any(utc_offset == input_utc_offset for utc_offset, _, _ in tzinfos):
# match timezones that have/had/will have the same utc offset
timezone_ids.add(tz.zone)
print(timezone_ids)
Output
{'America/Anguilla',
'America/Antigua',
'America/Argentina/Buenos_Aires',
...,
'Cuba',
'EST5EDT',
'Jamaica',
'US/East-Indiana',
'US/Eastern',
'US/Michigan'}
You can't even limit the list using pytz.country_timezones['us'] because it would exclude one of your examples: 'America/Puerto_Rico'.
If you know coordinates (latitude, longitude); you could get the timezone id from the shape file: you could use a local database or a web-service:
#!/usr/bin/env python
from geopy import geocoders # pip install "geopy[timezone]"
g = geocoders.GoogleV3()
for coords in [(18.4372, -67.159), (41.9782, -71.7679), (61.1895, -149.874)]:
print(g.timezone(coords).zone)
Output
America/Puerto_Rico
America/New_York
America/Anchorage
Note: some local times may be ambiguous e.g., when the time falls back during end of DST transition. You could pass is_dst=None to .localize() method to raise an exception in such cases.
Different versions of the tz database may have different utc offset for some timezones at some dates i.e., it is not enough to store UTC time and the timezone id (what version to use depends on your application).
How to get system timezone setting and pass it to pytz.timezone?
A very simple method to solve this question:
import time
def localTzname():
offsetHour = time.timezone / 3600
return 'Etc/GMT%+d' % offsetHour
Update: @MartijnPieters said 'This won't work with DST / summertime.' So how about this version?
import time
def localTzname():
if time.daylight:
offsetHour = time.altzone / 3600
else:
offsetHour = time.timezone / 3600
return 'Etc/GMT%+d' % offsetHour
Python: Figure out local timezone
Try dateutil, which has a tzlocal type that does what you need.
Python - Timezone name given timestamp UTC and UTC offset
You could loop through all the timezones
for name in pytz.all_timezones:
and compare the date's utcoffset to the given offset:
if date.utcoffset().total_seconds() == utcoffset:
result.append(name)
import datetime as DT
import pytz
utc = pytz.utc
def tzones(timestamp, utcoffset):
result = []
date = utc.localize(DT.datetime.utcfromtimestamp(timestamp/float(1000)))
for name in pytz.all_timezones:
timezone = pytz.timezone(name)
date = date.astimezone(timezone)
if date.utcoffset().total_seconds() == utcoffset:
result.append(name)
return result
print(tzones(1456865863633, -14400))
prints
['America/Anguilla', 'America/Antigua', 'America/Aruba', 'America/Barbados', 'America/Blanc-Sablon', 'America/Boa_Vista', 'America/Campo_Grande', 'America/Cuiaba', 'America/Curacao', 'America/Dominica', 'America/Glace_Bay', 'America/Goose_Bay', 'America/Grand_Turk', 'America/Grenada', 'America/Guadeloupe', 'America/Guyana', 'America/Halifax', 'America/Kralendijk', 'America/La_Paz', 'America/Lower_Princes', 'America/Manaus', 'America/Marigot', 'America/Martinique', 'America/Moncton', 'America/Montserrat', 'America/Port_of_Spain', 'America/Porto_Velho', 'America/Puerto_Rico', 'America/Santo_Domingo', 'America/St_Barthelemy', 'America/St_Kitts', 'America/St_Lucia', 'America/St_Thomas', 'America/St_Vincent', 'America/Thule', 'America/Tortola', 'America/Virgin', 'Atlantic/Bermuda', 'Brazil/West', 'Canada/Atlantic', 'Etc/GMT+4']
Getting Olson timezone ID information from browser via javascript
You can't directly access timezone in JavaScript. You can, however, measure offsets reported at several different specific dates to deduce what exactly time zone is in use by comparing regular and daylight savings times to database of zones. There's a jsTimezoneDetect library that can do most of this work for you.
.NET TimeZoneInfo from Olson time zone
This Unicode.org page has a "Olson time zone to Win32 time zone" table. From there, I created a nice little C# helper function to map from Olson time zone string into a .NET TimeZoneInfo:
/// <summary>
/// Converts an Olson time zone ID to a Windows time zone ID.
/// </summary>
/// <param name="olsonTimeZoneId">An Olson time zone ID. See http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/zone_tzid.html. </param>
/// <returns>
/// The TimeZoneInfo corresponding to the Olson time zone ID,
/// or null if you passed in an invalid Olson time zone ID.
/// </returns>
/// <remarks>
/// See http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/zone_tzid.html
/// </remarks>
public static TimeZoneInfo OlsonTimeZoneToTimeZoneInfo(string olsonTimeZoneId)
{
var olsonWindowsTimes = new Dictionary<string, string>()
{
{ "Africa/Bangui", "W. Central Africa Standard Time" },
{ "Africa/Cairo", "Egypt Standard Time" },
{ "Africa/Casablanca", "Morocco Standard Time" },
{ "Africa/Harare", "South Africa Standard Time" },
{ "Africa/Johannesburg", "South Africa Standard Time" },
{ "Africa/Lagos", "W. Central Africa Standard Time" },
{ "Africa/Monrovia", "Greenwich Standard Time" },
{ "Africa/Nairobi", "E. Africa Standard Time" },
{ "Africa/Windhoek", "Namibia Standard Time" },
{ "America/Anchorage", "Alaskan Standard Time" },
{ "America/Argentina/San_Juan", "Argentina Standard Time" },
{ "America/Asuncion", "Paraguay Standard Time" },
{ "America/Bahia", "Bahia Standard Time" },
{ "America/Bogota", "SA Pacific Standard Time" },
{ "America/Buenos_Aires", "Argentina Standard Time" },
{ "America/Caracas", "Venezuela Standard Time" },
{ "America/Cayenne", "SA Eastern Standard Time" },
{ "America/Chicago", "Central Standard Time" },
{ "America/Chihuahua", "Mountain Standard Time (Mexico)" },
{ "America/Cuiaba", "Central Brazilian Standard Time" },
{ "America/Denver", "Mountain Standard Time" },
{ "America/Fortaleza", "SA Eastern Standard Time" },
{ "America/Godthab", "Greenland Standard Time" },
{ "America/Guatemala", "Central America Standard Time" },
{ "America/Halifax", "Atlantic Standard Time" },
{ "America/Indianapolis", "US Eastern Standard Time" },
{ "America/Indiana/Indianapolis", "US Eastern Standard Time" },
{ "America/La_Paz", "SA Western Standard Time" },
{ "America/Los_Angeles", "Pacific Standard Time" },
{ "America/Mexico_City", "Mexico Standard Time" },
{ "America/Montevideo", "Montevideo Standard Time" },
{ "America/New_York", "Eastern Standard Time" },
{ "America/Noronha", "UTC-02" },
{ "America/Phoenix", "US Mountain Standard Time" },
{ "America/Regina", "Canada Central Standard Time" },
{ "America/Santa_Isabel", "Pacific Standard Time (Mexico)" },
{ "America/Santiago", "Pacific SA Standard Time" },
{ "America/Sao_Paulo", "E. South America Standard Time" },
{ "America/St_Johns", "Newfoundland Standard Time" },
{ "America/Tijuana", "Pacific Standard Time" },
{ "Antarctica/McMurdo", "New Zealand Standard Time" },
{ "Atlantic/South_Georgia", "UTC-02" },
{ "Asia/Almaty", "Central Asia Standard Time" },
{ "Asia/Amman", "Jordan Standard Time" },
{ "Asia/Baghdad", "Arabic Standard Time" },
{ "Asia/Baku", "Azerbaijan Standard Time" },
{ "Asia/Bangkok", "SE Asia Standard Time" },
{ "Asia/Beirut", "Middle East Standard Time" },
{ "Asia/Calcutta", "India Standard Time" },
{ "Asia/Colombo", "Sri Lanka Standard Time" },
{ "Asia/Damascus", "Syria Standard Time" },
{ "Asia/Dhaka", "Bangladesh Standard Time" },
{ "Asia/Dubai", "Arabian Standard Time" },
{ "Asia/Irkutsk", "North Asia East Standard Time" },
{ "Asia/Jerusalem", "Israel Standard Time" },
{ "Asia/Kabul", "Afghanistan Standard Time" },
{ "Asia/Kamchatka", "Kamchatka Standard Time" },
{ "Asia/Karachi", "Pakistan Standard Time" },
{ "Asia/Katmandu", "Nepal Standard Time" },
{ "Asia/Kolkata", "India Standard Time" },
{ "Asia/Krasnoyarsk", "North Asia Standard Time" },
{ "Asia/Kuala_Lumpur", "Singapore Standard Time" },
{ "Asia/Kuwait", "Arab Standard Time" },
{ "Asia/Magadan", "Magadan Standard Time" },
{ "Asia/Muscat", "Arabian Standard Time" },
{ "Asia/Novosibirsk", "N. Central Asia Standard Time" },
{ "Asia/Oral", "West Asia Standard Time" },
{ "Asia/Rangoon", "Myanmar Standard Time" },
{ "Asia/Riyadh", "Arab Standard Time" },
{ "Asia/Seoul", "Korea Standard Time" },
{ "Asia/Shanghai", "China Standard Time" },
{ "Asia/Singapore", "Singapore Standard Time" },
{ "Asia/Taipei", "Taipei Standard Time" },
{ "Asia/Tashkent", "West Asia Standard Time" },
{ "Asia/Tbilisi", "Georgian Standard Time" },
{ "Asia/Tehran", "Iran Standard Time" },
{ "Asia/Tokyo", "Tokyo Standard Time" },
{ "Asia/Ulaanbaatar", "Ulaanbaatar Standard Time" },
{ "Asia/Vladivostok", "Vladivostok Standard Time" },
{ "Asia/Yakutsk", "Yakutsk Standard Time" },
{ "Asia/Yekaterinburg", "Ekaterinburg Standard Time" },
{ "Asia/Yerevan", "Armenian Standard Time" },
{ "Atlantic/Azores", "Azores Standard Time" },
{ "Atlantic/Cape_Verde", "Cape Verde Standard Time" },
{ "Atlantic/Reykjavik", "Greenwich Standard Time" },
{ "Australia/Adelaide", "Cen. Australia Standard Time" },
{ "Australia/Brisbane", "E. Australia Standard Time" },
{ "Australia/Darwin", "AUS Central Standard Time" },
{ "Australia/Hobart", "Tasmania Standard Time" },
{ "Australia/Perth", "W. Australia Standard Time" },
{ "Australia/Sydney", "AUS Eastern Standard Time" },
{ "Etc/GMT", "UTC" },
{ "Etc/GMT+11", "UTC-11" },
{ "Etc/GMT+12", "Dateline Standard Time" },
{ "Etc/GMT+2", "UTC-02" },
{ "Etc/GMT-12", "UTC+12" },
{ "Europe/Amsterdam", "W. Europe Standard Time" },
{ "Europe/Athens", "GTB Standard Time" },
{ "Europe/Belgrade", "Central Europe Standard Time" },
{ "Europe/Berlin", "W. Europe Standard Time" },
{ "Europe/Brussels", "Romance Standard Time" },
{ "Europe/Budapest", "Central Europe Standard Time" },
{ "Europe/Dublin", "GMT Standard Time" },
{ "Europe/Helsinki", "FLE Standard Time" },
{ "Europe/Istanbul", "GTB Standard Time" },
{ "Europe/Kiev", "FLE Standard Time" },
{ "Europe/London", "GMT Standard Time" },
{ "Europe/Minsk", "E. Europe Standard Time" },
{ "Europe/Moscow", "Russian Standard Time" },
{ "Europe/Paris", "Romance Standard Time" },
{ "Europe/Sarajevo", "Central European Standard Time" },
{ "Europe/Warsaw", "Central European Standard Time" },
{ "Indian/Mauritius", "Mauritius Standard Time" },
{ "Pacific/Apia", "Samoa Standard Time" },
{ "Pacific/Auckland", "New Zealand Standard Time" },
{ "Pacific/Fiji", "Fiji Standard Time" },
{ "Pacific/Guadalcanal", "Central Pacific Standard Time" },
{ "Pacific/Guam", "West Pacific Standard Time" },
{ "Pacific/Honolulu", "Hawaiian Standard Time" },
{ "Pacific/Pago_Pago", "UTC-11" },
{ "Pacific/Port_Moresby", "West Pacific Standard Time" },
{ "Pacific/Tongatapu", "Tonga Standard Time" }
};
var windowsTimeZoneId = default(string);
var windowsTimeZone = default(TimeZoneInfo);
if (olsonWindowsTimes.TryGetValue(olsonTimeZoneId, out windowsTimeZoneId))
{
try { windowsTimeZone = TimeZoneInfo.FindSystemTimeZoneById(windowsTimeZoneId); }
catch (TimeZoneNotFoundException) { }
catch (InvalidTimeZoneException) { }
}
return windowsTimeZone;
}
Related Topics
Cqlsh Connection Error: 'Ref() Does Not Take Keyword Arguments'
Is There a Python Equivalent to Java'S Awt Robot Class
Selenium - Wait Until Element Is Present, Visible and Interactable
Is There a Difference Between "==" and "Is"
How to Parse an Iso 8601-Formatted Date
Get Statistics For Each Group (Such as Count, Mean, etc) Using Pandas Groupby
Python Regex Find All Overlapping Matches
How to Download a File Over Http
How Do "And" and "Or" Act With Non-Boolean Values
Django [Errno 13] Permission Denied: '/Var/Www/Media/Animals/User_Uploads'
How to Do Sed Like Text Replace With Python
Using Global Variables in a Function
Of the Many Findelement(S)/By Functions in Selenium, When Would You Use One Over the Other
How to Parse a String to a Float or Int
How Does Python'S Super() Work With Multiple Inheritance