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问题:
Every time I use:
time.strftime("%z")
I get:
Eastern Daylight Time
However, I would like the UTC offset in the form +HHMM or -HHMM. I have even tried:
time.strftime("%Z")
Which still yields:
Eastern Daylight Time
I have read several other posts related to strftime() and %z always seems to return the UTC offset in the proper +HHMM or -HHMM format. How do I get strftime() to output in the +HHMM or -HHMM format for python 3.3?
Edit: I'm running Windows 7
回答1:
For a proper solution, see abarnert’s answer below.
You can use time.altzone
which returns a negative offset in seconds. For example, I’m on CEST at the moment (UTC+2), so I get this:
>>> time.altzone
-7200
And to put it in your desired format:
>>> '{}{:0>2}{:0>2}'.format('-' if time.altzone > 0 else '+', abs(time.altzone) // 3600, abs(time.altzone // 60) % 60)
'+0200'
As abarnert mentioned in the comments, time.altzone
gives the offset when DST is active while time.timezone
does for when DST is not active. To figure out which to use, you can do what J.F. Sebastian suggested in his answer to a different question. So you can get the correct offset like this:
time.altzone if time.daylight and time.localtime().tm_isdst > 0 else time.timezone
As also suggested by him, you can use the following in Python 3 to get the desired format using datetime.timezone:
>>> datetime.now(timezone.utc).astimezone().strftime('%z')
'+0200'
回答2:
In 2.x, if you look at the docs for time.strftime
, they don't even mention %z
. It's not guaranteed to exist at all, much less to be consistent across platforms. In fact, as footnote 1 implies, it's left up to the C strftime
function. In 3.x, on the other hand, they do mention %z
, and the footnote that explains that it doesn't work the way you'd expect is not easy to see; that's an open bug.
However, in 2.6+ (including all 3.x versions), datetime.strftime
is guaranteed to support %z
as "UTC offset in the form +HHMM or -HHMM (empty string if the the object is naive)." So, that makes for a pretty easy workaround: use datetime
instead of time
. Exactly how to change things depends on what exactly you're trying to do — using Python-dateutil tz
then datetime.now(tz.tzlocal()).strftime('%z')
is the way to get just the local timezone formatted as a GMT offset, but if you're trying to format a complete time the details will be a little different.
If you look at the source, time.strftime
basically just checks the format string for valid-for-the-platform specifiers and calls the native strftime
function, while datetime.strftime
has a bunch of special handling for different specifiers, including %z
; in particular, it will replace the %z
with a formatted version of utcoffset
before passing things on to strftime
. The code has changed a few times since 2.7, and even been radically reorganized once, but the same difference is basically there even in the pre-3.5 trunk.
回答3:
Use time.timezone
to get the time offset in seconds.
Format it using :
("-" if time.timezone > 0 else "+") + time.strftime("%H:%M", time.gmtime(abs(time.timezone)))
to convert the same to +/-HH:MM format.
BTW isn't this supposed to be a bug ? According to strftime
docs.
Also I thought this SO answer might help you to convert from Zone offset string to HH:MM format. But since "%z"
is not working as expected, I feel its moot.
NOTE: The time.timezone
is immune to Daylight savings.
回答4:
It will come as no surprise that this bug persists in, what is the latest Windows version available currently, Win 10 Version 1703 (Creators). However, time marches on and there is a lovely date-and-time library called pendulum that does what the question asks for. Sébastien Eustace (principal author of the product?) has shown me this.
>>> pendulum.now().strftime('%z')
'-0400'
pendulum assumes UTC/GMT unless told otherwise, and keeps timezone with the date-time object. There are many other possibilities, amongst them these:
>>> pendulum.now(tz='Europe/Paris').strftime('%z')
'+0200'
>>> pendulum.create(year=2016, month=11, day=5, hour=16, minute=23, tz='America/Winnipeg').strftime('%z')
'-0500'
>>> pendulum.now(tz='America/Winnipeg').strftime('%z')
'-0500'