Python 如何将 datetime.time 从 UTC 转换为不同的时区？

How to convert datetime.time from UTC to different timezone?

提问by rajpy

I have variable which holds time which is of type datetime.time in UTC, I wanted it to convert to some other timezone.

我有一个保存时间的变量，它在 UTC 中是 datetime.time 类型，我希望它转换为其他时区。

we can convert timezones in datetime.datetime instance as shown in this SO link - How do I convert local time to UTC in Python?. I am not able to figure out how to convert timezones in datetime.time instances. I can't use astimezone because datetime.time doesn't have this method.

我们可以在 datetime.datetime 实例中转换时区，如此链接所示 -如何在 Python 中将本地时间转换为 UTC？. 我无法弄清楚如何在 datetime.time 实例中转换时区。我不能使用 astimezone 因为 datetime.time 没有这个方法。

For example:

例如：

>>> t = d.datetime.now().time()
>>> t
datetime.time(12, 56, 44, 398402)
>>> 

I need 't' in UTC format.

我需要UTC格式的't'。

采纳答案by Matt Johnson-Pint

You need pytz. The use case you describe is illustrated in their primary examples.

你需要pytz。您描述的用例在它们的主要示例中进行了说明。

回答by shx2

I would create a temp datetime object, convert the tz, and extract the time again.

我会创建一个临时日期时间对象，转换 tz，然后再次提取时间。

import datetime
def time_to_utc(t):
    dt = datetime.datetime.combine(datetime.date.today(), t)
    utc_dt = datetime_to_utc(dt)
    return utc_dt.time()

t = datetime.datetime.now().time()
utc_t = time_to_utc(t)

where, datetime_to_utcis any of the suggestions in the linked question.

其中，datetime_to_utc是链接问题中的任何建议。

回答by Tarek Kalaji

Easy way to convert from/to UTC timezone using pytz:

使用pytz从/到 UTC 时区的简单方法：

import datetime, pytz

def time_to_utc(naive, timezone="Europe/Istanbul"):
    local = pytz.timezone(timezone)
    local_dt = local.localize(naive, is_dst=None)
    utc_dt = local_dt.astimezone(pytz.utc)
    return utc_dt

def utc_to_time(naive, timezone="Europe/Istanbul"):
    return naive.replace(tzinfo=pytz.utc).astimezone(pytz.timezone(timezone))

# type(naive) """DateTime"""
# type(timezone) """String"""

回答by Dorian B.

There are four cases:

有四种情况：

1. input datetime.timehas tzinfoset (eg OP mentions UTC)
   1. output as non-naive time
   2. output as naive time (tzinfonot set)
2. input datetime.timehas tzinfonot set
   1. output as non-naive time
   2. output as naive time (tzinfonot set)

1. 输入datetime.time已tzinfo设置（例如 OP 提到 UTC）
   1. 输出为非初始时间
   2. 输出为初始时间（tzinfo未设置）
2. 输入datetime.time还tzinfo没有设置
   1. 输出为非初始时间
   2. 输出为初始时间（tzinfo未设置）

The correct answer needs to make use of datetime.datetime.timetz()function because datetime.timecannot be built as a non-naive timestamp by calling localize()or astimezone()directly.

正确答案需要使用datetime.datetime.timetz()函数，因为datetime.time不能通过调用localize()或astimezone()直接构建为非原始时间戳。

from datetime import datetime, time
import pytz

def timetz_to_tz(t, tz_out):
    return datetime.combine(datetime.today(), t).astimezone(tz_out).timetz()

def timetz_to_tz_naive(t, tz_out):
    return datetime.combine(datetime.today(), t).astimezone(tz_out).time()

def time_to_tz(t, tz_out):
    return tz_out.localize(datetime.combine(datetime.today(), t)).timetz()

def time_to_tz_naive(t, tz_in, tz_out):
    return tz_in.localize(datetime.combine(datetime.today(), t)).astimezone(tz_out).time()

Example based on OP requirement:

基于 OP 要求的示例：

t = time(12, 56, 44, 398402)
time_to_tz(t, pytz.utc) # assigning tzinfo= directly would not work correctly with other timezones

datetime.time(12, 56, 44, 398402, tzinfo=<UTC>)

In case naive timestamp is wanted:

如果需要朴素的时间戳：

time_to_tz_naive(t, pytz.utc, pytz.timezone('Europe/Berlin'))

datetime.time(14, 56, 44, 398402)

The cases where the time() instance has already tzinfoset are easier because datetime.combinepicks up the tzinfofrom the passed parameter, so we just need to convert to tz_out.

其中时间（）实例已经案件tzinfo设置更容易，因为datetime.combine拾取tzinfo从传递的参数，所以我们只需要转换为tz_out。