问题：在Python中将datetime.date转换为UTC时间戳
我正在使用Python处理日期，因此需要将其转换为UTC时间戳以在Javascript中使用。以下代码不起作用：
>>> d = datetime.date(2011,01,01)
>>> datetime.datetime.utcfromtimestamp(time.mktime(d.timetuple()))
datetime.datetime(2010, 12, 31, 23, 0)
首先将日期对象转换为datetime也无济于事。我从以下链接尝试了此示例，但是：
from pytz import utc, timezone
from datetime import datetime
from time import mktime
input_date = datetime(year=2011, month=1, day=15)
现在要么：
mktime(utc.localize(input_date).utctimetuple())
要么
mktime(timezone('US/Eastern').localize(input_date).utctimetuple())
确实有效。
如此普遍的问题：如何根据UTC将日期转换为自纪元以来的秒数？
I am dealing with dates in Python and I need to convert them to UTC timestamps to be used
inside Javascript. The following code does not work:
>>> d = datetime.date(2011,01,01)
>>> datetime.datetime.utcfromtimestamp(time.mktime(d.timetuple()))
datetime.datetime(2010, 12, 31, 23, 0)
Converting the date object first to datetime also does not help. I tried the example at this link from, but:
from pytz import utc, timezone
from datetime import datetime
from time import mktime
input_date = datetime(year=2011, month=1, day=15)
and now either:
mktime(utc.localize(input_date).utctimetuple())
or
mktime(timezone('US/Eastern').localize(input_date).utctimetuple())
does work.
So general question: how can I get a date converted to seconds since epoch according to UTC?
回答 0
如果d = date(2011, 1, 1)使用UTC：
>>> from datetime import datetime, date
>>> import calendar
>>> timestamp1 = calendar.timegm(d.timetuple())
>>> datetime.utcfromtimestamp(timestamp1)
datetime.datetime(2011, 1, 1, 0, 0)
如果d在当地时区：
>>> import time
>>> timestamp2 = time.mktime(d.timetuple()) # DO NOT USE IT WITH UTC DATE
>>> datetime.fromtimestamp(timestamp2)
datetime.datetime(2011, 1, 1, 0, 0)
timestamp1而timestamp2如果午夜在本地时区是不一样的时间实例作为午夜UTC可能会有所不同。
mktime()如果d对应于一个不明确的本地时间（例如，在DST过渡期间），或者d是utc偏移可能已经不同并且 C mktime()无法访问给定平台上的tz数据库的过去（未来）日期，则可能返回错误结果。您可以使用pytz模块（例如via tzlocal.get_localzone()）来访问所有平台上的tz数据库。此外，如果使用timezone，则utcfromtimestamp()可能会失败并mktime()可能返回非POSIX时间戳"right"。
要转换datetime.date不使用UTC表示日期的对象calendar.timegm()：
DAY = 24*60*60 # POSIX day in seconds (exact value)
timestamp = (utc_date.toordinal() - date(1970, 1, 1).toordinal()) * DAY
timestamp = (utc_date - date(1970, 1, 1)).days * DAY
如何根据UTC将日期转换为自纪元以来的秒数？
将已经以UTC表示时间的对象datetime.datetime（不是datetime.date）转换为相应的POSIX时间戳（a float）。
Python 3.3以上
datetime.timestamp()：
from datetime import timezone
timestamp = dt.replace(tzinfo=timezone.utc).timestamp()
注意：有必要timezone.utc明确地提供其他条件，.timestamp()假设您朴素的datetime对象位于本地时区。
Python 3（<3.3）
从文档中获取datetime.utcfromtimestamp()：
没有从日期时间实例获取时间戳的方法，但是可以很容易地如下计算对应于日期时间实例dt的POSIX时间戳。对于幼稚的dt：
timestamp = (dt - datetime(1970, 1, 1)) / timedelta(seconds=1)
对于有意识的dt：
timestamp = (dt - datetime(1970,1,1, tzinfo=timezone.utc)) / timedelta(seconds=1)
有趣的读物：大纪元时间与一天中的时间之间的时差是几点？和多少秒过去了？
另请参见：datetime需要一种“时代”方法
Python 2
为了使以上代码适用于Python 2：
timestamp = (dt - datetime(1970, 1, 1)).total_seconds()
其中timedelta.total_seconds()等于在(td.microseconds + (td.seconds + td.days * 24 * 3600) * 10**6) / 10**6启用真除法的情况下进行的计算。
from __future__ import division
from datetime import datetime, timedelta
def totimestamp(dt, epoch=datetime(1970,1,1)):
td = dt - epoch
# return td.total_seconds()
return (td.microseconds + (td.seconds + td.days * 86400) * 10**6) / 10**6
now = datetime.utcnow()
print now
print totimestamp(now)
当心浮点问题。
输出量
2012-01-08 15:34:10.022403
1326036850.02
如何将感知datetime对象转换为POSIX时间戳
assert dt.tzinfo is not None and dt.utcoffset() is not None
timestamp = dt.timestamp() # Python 3.3+
在Python 3上：
from datetime import datetime, timedelta, timezone
epoch = datetime(1970, 1, 1, tzinfo=timezone.utc)
timestamp = (dt - epoch) / timedelta(seconds=1)
integer_timestamp = (dt - epoch) // timedelta(seconds=1)
在Python 2上：
# utc time = local time - utc offset
utc_naive = dt.replace(tzinfo=None) - dt.utcoffset()
timestamp = (utc_naive - datetime(1970, 1, 1)).total_seconds()
If d = date(2011, 1, 1) is in UTC:
>>> from datetime import datetime, date
>>> import calendar
>>> timestamp1 = calendar.timegm(d.timetuple())
>>> datetime.utcfromtimestamp(timestamp1)
datetime.datetime(2011, 1, 1, 0, 0)
If d is in local timezone:
>>> import time
>>> timestamp2 = time.mktime(d.timetuple()) # DO NOT USE IT WITH UTC DATE
>>> datetime.fromtimestamp(timestamp2)
datetime.datetime(2011, 1, 1, 0, 0)
timestamp1 and timestamp2 may differ if midnight in the local timezone is not the same time instance as midnight in UTC.
mktime() may return a wrong result if d corresponds to an ambiguous local time (e.g., during DST transition) or if d is a past(future) date when the utc offset might have been different and the C mktime() has no access to the tz database on the given platform. You could use pytz module (e.g., via tzlocal.get_localzone()) to get access to the tz database on all platforms. Also, utcfromtimestamp() may fail and mktime() may return non-POSIX timestamp if "right" timezone is used.
To convert datetime.date object that represents date in UTC without calendar.timegm():
DAY = 24*60*60 # POSIX day in seconds (exact value)
timestamp = (utc_date.toordinal() - date(1970, 1, 1).toordinal()) * DAY
timestamp = (utc_date - date(1970, 1, 1)).days * DAY
How can I get a date converted to seconds since epoch according to UTC?
To convert datetime.datetime (not datetime.date) object that already represents time in UTC to the corresponding POSIX timestamp (a float).
Python 3.3+
datetime.timestamp():
from datetime import timezone
timestamp = dt.replace(tzinfo=timezone.utc).timestamp()
Note: It is necessary to supply timezone.utc explicitly otherwise .timestamp() assume that your naive datetime object is in local timezone.
Python 3 (< 3.3)
From the docs for datetime.utcfromtimestamp():
There is no method to obtain the timestamp from a datetime instance,
but POSIX timestamp corresponding to a datetime instance dt can be
easily calculated as follows. For a naive dt:
timestamp = (dt - datetime(1970, 1, 1)) / timedelta(seconds=1)
And for an aware dt:
timestamp = (dt - datetime(1970,1,1, tzinfo=timezone.utc)) / timedelta(seconds=1)
Interesting read: Epoch time vs. time of day on the difference between What time is it? and How many seconds have elapsed?
See also: datetime needs an “epoch” method
Python 2
To adapt the above code for Python 2:
timestamp = (dt - datetime(1970, 1, 1)).total_seconds()
where timedelta.total_seconds() is equivalent to (td.microseconds + (td.seconds + td.days * 24 * 3600) * 10**6) / 10**6 computed with true division enabled.
from __future__ import division
from datetime import datetime, timedelta
def totimestamp(dt, epoch=datetime(1970,1,1)):
td = dt - epoch
# return td.total_seconds()
return (td.microseconds + (td.seconds + td.days * 86400) * 10**6) / 10**6
now = datetime.utcnow()
print now
print totimestamp(now)
Beware of floating-point issues.
Output
2012-01-08 15:34:10.022403
1326036850.02
How to convert an aware datetime object to POSIX timestamp
assert dt.tzinfo is not None and dt.utcoffset() is not None
timestamp = dt.timestamp() # Python 3.3+
On Python 3:
from datetime import datetime, timedelta, timezone
epoch = datetime(1970, 1, 1, tzinfo=timezone.utc)
timestamp = (dt - epoch) / timedelta(seconds=1)
integer_timestamp = (dt - epoch) // timedelta(seconds=1)
On Python 2:
# utc time = local time - utc offset
utc_naive = dt.replace(tzinfo=None) - dt.utcoffset()
timestamp = (utc_naive - datetime(1970, 1, 1)).total_seconds()
回答 1
仅适用于Unix系统：
>>> import datetime
>>> d = datetime.date(2011,01,01)
>>> d.strftime("%s") # <-- THIS IS THE CODE YOU WANT
'1293832800'
注1： dizzyf观察到这适用于本地时区。不要在生产中使用。
注意2： JakubNarębski指出，即使对于具有偏移量的日期时间，它也会忽略时区信息（已针对Python 2.7测试）。
For unix systems only:
>>> import datetime
>>> d = datetime.date(2011,01,01)
>>> d.strftime("%s") # <-- THIS IS THE CODE YOU WANT
'1293832800'
Note 1: dizzyf observed that this applies localized timezones. Don’t use in production.
Note 2: Jakub Narębski noted that this ignores timezone information even for offset-aware datetime (tested for Python 2.7).
回答 2
首先，您可以使用timetuple()成员将日期实例转换为代表各种时间成分的元组：
dtt = d.timetuple() # time.struct_time(tm_year=2011, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=5, tm_yday=1, tm_isdst=-1)
然后，您可以使用将该时间戳转换为时间戳time.mktime：
ts = time.mktime(dtt) # 1293868800.0
您可以通过使用纪元时间本身（1970-01-01）对其进行测试来验证此方法，在这种情况下，该函数应返回该日期的本地时区的时区偏移量：
d = datetime.date(1970,1,1)
dtt = d.timetuple() # time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=-1)
ts = time.mktime(dtt) # 28800.0
28800.0 是8个小时，这对于太平洋时区（我所在的时间）是正确的。
Assumption 1: You’re attempting to convert a date to a timestamp, however since a date covers a 24 hour period, there isn’t a single timestamp that represents that date. I’ll assume that you want to represent the timestamp of that date at midnight (00:00:00.000).
Assumption 2: The date you present is not associated with a particular time zone, however you want to determine the offset from a particular time zone (UTC). Without knowing the time zone the date is in, it isn’t possible to calculate a timestamp for a specific time zone. I’ll assume that you want to treat the date as if it is in the local system time zone.
First, you can convert the date instance into a tuple representing the various time components using the timetuple() member:
dtt = d.timetuple() # time.struct_time(tm_year=2011, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=5, tm_yday=1, tm_isdst=-1)
You can then convert that into a timestamp using time.mktime:
ts = time.mktime(dtt) # 1293868800.0
You can verify this method by testing it with the epoch time itself (1970-01-01), in which case the function should return the timezone offset for the local time zone on that date:
d = datetime.date(1970,1,1)
dtt = d.timetuple() # time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=-1)
ts = time.mktime(dtt) # 28800.0
28800.0 is 8 hours, which would be correct for the Pacific time zone (where I’m at).
回答 3
按照python2.7文档，您必须使用calendar.timegm（）而不是time.mktime（）
>>> d = datetime.date(2011,01,01)
>>> datetime.datetime.utcfromtimestamp(calendar.timegm(d.timetuple()))
datetime.datetime(2011, 1, 1, 0, 0)
follow the python2.7 document, you have to use calendar.timegm() instead of time.mktime()
>>> d = datetime.date(2011,01,01)
>>> datetime.datetime.utcfromtimestamp(calendar.timegm(d.timetuple()))
datetime.datetime(2011, 1, 1, 0, 0)
回答 4
我定义了我自己的两个功能
- utc_time2datetime（utc_time，tz =无）
- datetime2utc_time（日期时间）
这里：
import time
import datetime
from pytz import timezone
import calendar
import pytz
def utc_time2datetime(utc_time, tz=None):
# convert utc time to utc datetime
utc_datetime = datetime.datetime.fromtimestamp(utc_time)
# add time zone to utc datetime
if tz is None:
tz_datetime = utc_datetime.astimezone(timezone('utc'))
else:
tz_datetime = utc_datetime.astimezone(tz)
return tz_datetime
def datetime2utc_time(datetime):
# add utc time zone if no time zone is set
if datetime.tzinfo is None:
datetime = datetime.replace(tzinfo=timezone('utc'))
# convert to utc time zone from whatever time zone the datetime is set to
utc_datetime = datetime.astimezone(timezone('utc')).replace(tzinfo=None)
# create a time tuple from datetime
utc_timetuple = utc_datetime.timetuple()
# create a time element from the tuple an add microseconds
utc_time = calendar.timegm(utc_timetuple) + datetime.microsecond / 1E6
return utc_time
I defined my own two functions
- utc_time2datetime(utc_time, tz=None)
- datetime2utc_time(datetime)
here:
import time
import datetime
from pytz import timezone
import calendar
import pytz
def utc_time2datetime(utc_time, tz=None):
# convert utc time to utc datetime
utc_datetime = datetime.datetime.fromtimestamp(utc_time)
# add time zone to utc datetime
if tz is None:
tz_datetime = utc_datetime.astimezone(timezone('utc'))
else:
tz_datetime = utc_datetime.astimezone(tz)
return tz_datetime
def datetime2utc_time(datetime):
# add utc time zone if no time zone is set
if datetime.tzinfo is None:
datetime = datetime.replace(tzinfo=timezone('utc'))
# convert to utc time zone from whatever time zone the datetime is set to
utc_datetime = datetime.astimezone(timezone('utc')).replace(tzinfo=None)
# create a time tuple from datetime
utc_timetuple = utc_datetime.timetuple()
# create a time element from the tuple an add microseconds
utc_time = calendar.timegm(utc_timetuple) + datetime.microsecond / 1E6
return utc_time
回答 5
这个问题有点困惑。时间戳不是UTC，而是Unix。日期可能是UTC？假设是这样，并且如果您使用的是Python 3.2+，则简单日期使此操作变得无关紧要：
>>> SimpleDate(date(2011,1,1), tz='utc').timestamp
1293840000.0
如果您实际上有年，月和日，则无需创建date：
>>> SimpleDate(2011,1,1, tz='utc').timestamp
1293840000.0
以及日期是否在其他时区中（这很重要，因为我们假设午夜没有相关的时间）：
>>> SimpleDate(date(2011,1,1), tz='America/New_York').timestamp
1293858000.0
[simple-date背后的想法是将所有python的日期和时间收集在一个一致的类中，因此您可以进行任何转换。因此，例如，它也会沿相反方向前进：
>>> SimpleDate(1293858000, tz='utc').date
datetime.date(2011, 1, 1)
]
the question is a little confused. timestamps are not UTC – they’re a Unix thing. the date might be UTC? assuming it is, and if you’re using Python 3.2+, simple-date makes this trivial:
>>> SimpleDate(date(2011,1,1), tz='utc').timestamp
1293840000.0
if you actually have the year, month and day you don’t need to create the date:
>>> SimpleDate(2011,1,1, tz='utc').timestamp
1293840000.0
and if the date is in some other timezone (this matters because we’re assuming midnight without an associated time):
>>> SimpleDate(date(2011,1,1), tz='America/New_York').timestamp
1293858000.0
[the idea behind simple-date is to collect all python’s date and time stuff in one consistent class, so you can do any conversion. so, for example, it will also go the other way:
>>> SimpleDate(1293858000, tz='utc').date
datetime.date(2011, 1, 1)
]
回答 6
使用箭头包：
>>> import arrow
>>> arrow.get(2010, 12, 31).timestamp
1293753600
>>> time.gmtime(1293753600)
time.struct_time(tm_year=2010, tm_mon=12, tm_mday=31,
tm_hour=0, tm_min=0, tm_sec=0,
tm_wday=4, tm_yday=365, tm_isdst=0)
Using the arrow package:
>>> import arrow
>>> arrow.get(2010, 12, 31).timestamp
1293753600
>>> time.gmtime(1293753600)
time.struct_time(tm_year=2010, tm_mon=12, tm_mday=31,
tm_hour=0, tm_min=0, tm_sec=0,
tm_wday=4, tm_yday=365, tm_isdst=0)
回答 7
完整的时间字符串包含：
- 日期
- 时间
- utcoffset
[+HHMM or -HHMM]
例如：
1970-01-01 06:00:00 +0500 == 1970-01-01 01:00:00 +0000 == UNIX timestamp:3600
$ python3
>>> from datetime import datetime
>>> from calendar import timegm
>>> tm = '1970-01-01 06:00:00 +0500'
>>> fmt = '%Y-%m-%d %H:%M:%S %z'
>>> timegm(datetime.strptime(tm, fmt).utctimetuple())
3600
注意：
UNIX timestamp是一个浮点数，以纪元以来的秒数表示，单位为UTC。
编辑：
$ python3
>>> from datetime import datetime, timezone, timedelta
>>> from calendar import timegm
>>> dt = datetime(1970, 1, 1, 6, 0)
>>> tz = timezone(timedelta(hours=5))
>>> timegm(dt.replace(tzinfo=tz).utctimetuple())
3600
A complete time-string contains:
- date
- time
- utcoffset
[+HHMM or -HHMM]
For example:
1970-01-01 06:00:00 +0500 == 1970-01-01 01:00:00 +0000 == UNIX timestamp:3600
$ python3
>>> from datetime import datetime
>>> from calendar import timegm
>>> tm = '1970-01-01 06:00:00 +0500'
>>> fmt = '%Y-%m-%d %H:%M:%S %z'
>>> timegm(datetime.strptime(tm, fmt).utctimetuple())
3600
Note:
UNIX timestamp is a floating point number expressed in seconds since the epoch, in UTC.
Edit:
$ python3
>>> from datetime import datetime, timezone, timedelta
>>> from calendar import timegm
>>> dt = datetime(1970, 1, 1, 6, 0)
>>> tz = timezone(timedelta(hours=5))
>>> timegm(dt.replace(tzinfo=tz).utctimetuple())
3600
回答 8
考虑到您有一个datetime名为的对象d，请使用以下命令获取UTC中的时间戳记：
d.strftime("%Y-%m-%dT%H:%M:%S.%fZ")
对于相反的方向，请使用以下命令：
d = datetime.strptime("2008-09-03T20:56:35.450686Z", "%Y-%m-%dT%H:%M:%S.%fZ")
Considering you have a datetime object called d,
use the following to get the timestamp in UTC:
d.strftime("%Y-%m-%dT%H:%M:%S.%fZ")
And for the opposite direction, use following :
d = datetime.strptime("2008-09-03T20:56:35.450686Z", "%Y-%m-%dT%H:%M:%S.%fZ")
回答 9
我对深入的讨论印象深刻。
我的2美分：
从datetime导入datetime导入时间
utc中的时间戳为：
timestamp = \
(datetime.utcnow() - datetime(1970,1,1)).total_seconds()
要么，
timestamp = time.time()
如果现在是从datetime.now（）返回的，则在同一DST中
utcoffset = (datetime.now() - datetime.utcnow()).total_seconds()
timestamp = \
(now - datetime(1970,1,1)).total_seconds() - utcoffset
i’m impressed of the deep discussion.
my 2 cents:
from datetime import datetime
import time
the timestamp in utc is:
timestamp = \
(datetime.utcnow() - datetime(1970,1,1)).total_seconds()
or,
timestamp = time.time()
if now results from datetime.now(), in the same DST
utcoffset = (datetime.now() - datetime.utcnow()).total_seconds()
timestamp = \
(now - datetime(1970,1,1)).total_seconds() - utcoffset
