如何将本地时间的datetime字符串转换为UTC时间的字符串?
我确信我以前做过这个,但找不到它,所以希望将来能帮助我(和其他人)做到这一点。
澄清:例如,如果我的本地时区(+10)是2008-09-17 14:02:00,我希望生成一个具有等效UTC时间的字符串:2008-09-17 04:02:00。
此外,从http://lucumr.pocoo.org/2011/7/15/eppur-si-muove/请注意,一般来说,这是不可能的,因为DST和其他问题没有从本地时间到UTC时间的唯一转换。
下面是一些常见的Python时间转换的总结。
有些方法以秒为单位,用(s)标记。可以使用显式公式,如ts = (d - epoch) / unit代替(感谢jfs)。
struct_time (UTC) → POSIX (s):calendar.timegm(struct_time)
Naïve datetime (local) → POSIX (s):calendar.timegm(stz.localize(dt, is_dst=None).utctimetuple())(exception during DST transitions, see comment from jfs)
Naïve datetime (UTC) → POSIX (s):calendar.timegm(dt.utctimetuple())
Aware datetime → POSIX (s):calendar.timegm(dt.utctimetuple())
POSIX → struct_time (UTC, s):time.gmtime(t)(see comment from jfs)
Naïve datetime (local) → struct_time (UTC, s):stz.localize(dt, is_dst=None).utctimetuple()(exception during DST transitions, see comment from jfs)
Naïve datetime (UTC) → struct_time (UTC, s):dt.utctimetuple()
Aware datetime → struct_time (UTC, s):dt.utctimetuple()
POSIX → Naïve datetime (local):datetime.fromtimestamp(t, None)(may fail in certain conditions, see comment from jfs below)
struct_time (UTC) → Naïve datetime (local, s):datetime.datetime(struct_time[:6], tzinfo=UTC).astimezone(tz).replace(tzinfo=None)(can't represent leap seconds, see comment from jfs)
Naïve datetime (UTC) → Naïve datetime (local):dt.replace(tzinfo=UTC).astimezone(tz).replace(tzinfo=None)
Aware datetime → Naïve datetime (local):dt.astimezone(tz).replace(tzinfo=None)
POSIX → Naïve datetime (UTC):datetime.utcfromtimestamp(t)
struct_time (UTC) → Naïve datetime (UTC, s):datetime.datetime(*struct_time[:6])(can't represent leap seconds, see comment from jfs)
Naïve datetime (local) → Naïve datetime (UTC):stz.localize(dt, is_dst=None).astimezone(UTC).replace(tzinfo=None)(exception during DST transitions, see comment from jfs)
Aware datetime → Naïve datetime (UTC):dt.astimezone(UTC).replace(tzinfo=None)
POSIX → Aware datetime:datetime.fromtimestamp(t, tz)(may fail for non-pytz timezones)
struct_time (UTC) → Aware datetime (s):datetime.datetime(struct_time[:6], tzinfo=UTC).astimezone(tz)(can't represent leap seconds, see comment from jfs)
Naïve datetime (local) → Aware datetime:stz.localize(dt, is_dst=None)(exception during DST transitions, see comment from jfs)
Naïve datetime (UTC) → Aware datetime:dt.replace(tzinfo=UTC)
来源:taaviburns.ca
首先,将字符串解析为简单的datetime对象。这是datetime的一个实例。没有附加时区信息的日期时间。请参阅其文档。
使用pytz模块,该模块提供了时区+ UTC的完整列表。找出本地时区是什么,从它构造一个timezone对象,并操作它并将其附加到naive datetime。
最后,使用datetime.astimezone()方法将datetime转换为UTC。
源代码,使用本地时区“America/Los_Angeles”,用于字符串“2001-2-3 10:11:12”:
from datetime import datetime
import pytz
local = pytz.timezone("America/Los_Angeles")
naive = datetime.strptime("2001-2-3 10:11:12", "%Y-%m-%d %H:%M:%S")
local_dt = local.localize(naive, is_dst=None)
utc_dt = local_dt.astimezone(pytz.utc)
从那里,你可以使用strftime()方法来格式化UTC日期时间:
utc_dt.strftime("%Y-%m-%d %H:%M:%S")
谢谢@rofly,从字符串到字符串的完整转换如下:
import time
time.strftime("%Y-%m-%d %H:%M:%S",
time.gmtime(time.mktime(time.strptime("2008-09-17 14:04:00",
"%Y-%m-%d %H:%M:%S"))))
我对时间/日历功能的总结:
time.strptime
字符串——>元组(没有应用时区,所以匹配字符串)
time.mktime
本地时间元组——自epoch以来>秒(始终是本地时间)
time.gmtime
seconds since epoch——UTC中的>元组
and
calendar.timegm
tuple in UTC——> seconds since epoch
time.localtime
自epoch ->元组在本地时区的秒数