问题
I have to convert a timezone-aware string to python datetime object.
For example 2012-11-01T04:16:13-04:00.
I find there\'s a dateutil module which have a parse function to do it, but I don\'t really want to use it as it adds a dependency.
So how can I do it? I have tried something like the following, but with no luck.
datetime.datetime.strptime(\"2012-11-01T04:16:13-04:00\", \"%Y-%m-%dT%H:%M:%S%Z\")
回答1:
As of Python 3.7, datetime.datetime.fromisoformat() can handle your format:
>>> import datetime
>>> datetime.datetime.fromisoformat('2012-11-01T04:16:13-04:00')
datetime.datetime(2012, 11, 1, 4, 16, 13, tzinfo=datetime.timezone(datetime.timedelta(days=-1, seconds=72000)))
In older Python versions you can't, not without a whole lot of painstaking manual timezone defining.
Python does not include a timezone database, because it would be outdated too quickly. Instead, Python relies on external libraries, which can have a far faster release cycle, to provide properly configured timezones for you.
As a side-effect, this means that timezone parsing also needs to be an external library. If dateutil is too heavy-weight for you, use iso8601 instead, it'll parse your specific format just fine:
>>> import iso8601
>>> iso8601.parse_date('2012-11-01T04:16:13-04:00')
datetime.datetime(2012, 11, 1, 4, 16, 13, tzinfo=<FixedOffset '-04:00'>)
iso8601 is a whopping 4KB small. Compare that tot python-dateutil's 148KB.
As of Python 3.2 Python can handle simple offset-based timezones, and %z will parse -hhmm and +hhmm timezone offsets in a timestamp. That means that for a ISO 8601 timestamp you'd have to remove the : in the timezone:
>>> from datetime import datetime
>>> iso_ts = '2012-11-01T04:16:13-04:00'
>>> datetime.strptime(''.join(iso_ts.rsplit(':', 1)), '%Y-%m-%dT%H:%M:%S%z')
datetime.datetime(2012, 11, 1, 4, 16, 13, tzinfo=datetime.timezone(datetime.timedelta(-1, 72000)))
The lack of proper ISO 8601 parsing is being tracked in Python issue 15873.
回答2:
Here is the Python Doc for datetime object using dateutil package..
from dateutil.parser import parse
get_date_obj = parse("2012-11-01T04:16:13-04:00")
print get_date_obj
回答3:
There are two issues with the code in the original question: there should not be a : in the timezone and the format string for "timezone as an offset" is lower case %z not upper %Z.
This works for me in Python v3.6
>>> from datetime import datetime
>>> t = datetime.strptime("2012-11-01T04:16:13-0400", "%Y-%m-%dT%H:%M:%S%z")
>>> print(t)
2012-11-01 04:16:13-04:00
回答4:
I'm new to Python, but found a way to convert
2017-05-27T07:20:18.000-04:00
to
2017-05-27T07:20:18 without downloading new utilities.
from datetime import datetime, timedelta
time_zone1 = int("2017-05-27T07:20:18.000-04:00"[-6:][:3])
>>returns -04
item_date = datetime.strptime("2017-05-27T07:20:18.000-04:00".replace(".000", "")[:-6], "%Y-%m-%dT%H:%M:%S") + timedelta(hours=-time_zone1)
I'm sure there are better ways to do this without slicing up the string so much, but this got the job done.
回答5:
You can convert like this.
date = datetime.datetime.strptime('2019-3-16T5-49-52-595Z','%Y-%m-%dT%H-%M-%S-%f%z')
date_time = date.strftime('%Y-%m-%dT%H:%M:%S.%fZ')
来源：https://stackoverflow.com/questions/13182075/how-to-convert-a-timezone-aware-string-to-datetime-in-python-without-dateutil