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
下面是Python3.9中本地zoneinfo模块的示例:
from datetime import datetime
from zoneinfo import ZoneInfo
# Get timezone we're trying to convert from
local_tz = ZoneInfo("America/New_York")
# UTC timezone
utc_tz = ZoneInfo("UTC")
dt = datetime.strptime("2021-09-20 17:20:00","%Y-%m-%d %H:%M:%S")
dt = dt.replace(tzinfo=local_tz)
dt_utc = dt.astimezone(utc_tz)
print(dt.strftime("%Y-%m-%d %H:%M:%S"))
print(dt_utc.strftime("%Y-%m-%d %H:%M:%S"))
在转换的时区不反映系统本地时区的情况下,这可能比仅使用dt.astimezone()更可取。不必依赖外部库也很好。
注意:这可能在Windows系统上不起作用,因为zoneinfo依赖于可能不存在的IANA数据库。tzdata包可以作为解决方案安装。它是第一方包,但不在标准库中。
简单的
我是这样做的:
>>> utc_delta = datetime.utcnow()-datetime.now()
>>> utc_time = datetime(2008, 9, 17, 14, 2, 0) + utc_delta
>>> print(utc_time)
2008-09-17 19:01:59.999996
的实现
如果你想更花哨一点,你可以把它变成一个函子:
class to_utc():
utc_delta = datetime.utcnow() - datetime.now()
def __call__(cls, t):
return t + cls.utc_delta
结果:
>>> utc_converter = to_utc()
>>> print(utc_converter(datetime(2008, 9, 17, 14, 2, 0)))
2008-09-17 19:01:59.999996