Asp Forum - ISO with timezone

nikbaer

1/29/2008 2:03:00 AM

Hi,

How does one express the time in ISO format with the timezone
designator?

what I want is YYYY-MM-DDThh:mm:ss.sTZD

From the documentation I see:
>>> from datetime import tzinfo, timedelta, datetime
>>> class TZ(tzinfo):
.... def utcoffset(self, dt): return timedelta(minutes=-399)
....
>>> datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ')
'2002-12-25 00:00:00-06:39'

and I've also figured out:
>>>datetime.datetime.fromtimestamp(time.time()).isoformat()[:-3]
'2008-01-23T11:22:54.130'

But can't figure out how to fit them together.

Thank you,
Nik

6 Answers

Nicholas F. Fabry

1/29/2008 5:10:00 AM

Hello, nik.

On Jan 28, 2008, at 21:03, nik wrote:

> Hi,
>
> How does one express the time in ISO format with the timezone
> designator?
>
> what I want is YYYY-MM-DDThh:mm:ss.sTZD
>
>> From the documentation I see:
>>>> from datetime import tzinfo, timedelta, datetime
>>>> class TZ(tzinfo):
> ... def utcoffset(self, dt): return timedelta(minutes=-399)
> ...
>>>> datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ')
> '2002-12-25 00:00:00-06:39'
>
> and I've also figured out:
>>>> datetime.datetime.fromtimestamp(time.time()).isoformat()[:-3]
> '2008-01-23T11:22:54.130'
>
> But can't figure out how to fit them together.
>

There is nothing there to 'fit together' - in the first example given,
the datetime object has no time component specified, so it fills in
default vaules of zero. The following should make this clear:

>>> your_time = datetime(2008, 2, 29, 15, 30, 11, tzinfo=TZ())
>>> print your_time
2008-02-29 15:30:11-05:00
>>> print your_time.isoformat('T')
2008-02-29T15:30:11-05:00

If you wish to append the NAME of the tzinfo object instead of its
offset, that requires a bit more playing around (along with a properly
defined tzinfo object - check out dateutil or pytz for a concrete
implementation of tzinfo subclasses (i.e. timezones)), but the
following would work:

>>> print your_time.strftime('%Y-%m-%dT%H:%M:%S %Z')
2008-02-29T15:30:11 EST

For details on how the .strftime method works, see Python Standard
Library, Section 14.2.

I hope this helps!

Nick Fabry

> Thank you,
> Nik
> --
> http://mail.python.org/mailman/listinfo/p...

nikbaer

1/29/2008 6:56:00 PM

Thanks,
that does help and now I have:

>>> from datetime import datetime, tzinfo, timedelta
>>> import time
>>> class TZ(tzinfo):
.... def utcoffset(self,dt): return timedelta(seconds=time.timezone)
....
>>> print datetime(2008,2,29,15,30,11,tzinfo=TZ()).isoformat()
2008-02-29T15:30:11+8:00

But what I want to know now it how to get the actual time into the
expression instead of typing the 2008,2,29,15....
So something like: >>> print
datetime(time.gmtime(),tzinfo=TZ()).isoformat(), but that doesn't
work.

I realize that I could do:
>>> t = time.gmtime()
>>> print datetime(t[0],t[1],t[2],t[3],t[4],t[5],tzinfo=TZ()).isoformat()

but I imagine there might be a cleaner way of doing this.

Thanks,
Nik

On Jan 28, 9:10 pm, "Nicholas F. Fabry" <nick.fa...@coredump.us>
wrote:
> Hello, nik.
>
> On Jan 28, 2008, at 21:03, nik wrote:
>
>
>
> > Hi,
>
> > How does one express the time in ISO format with the timezone
> > designator?
>
> > what I want is YYYY-MM-DDThh:mm:ss.sTZD
>
> >> From the documentation I see:
> >>>> from datetime import tzinfo, timedelta, datetime
> >>>> class TZ(tzinfo):
> > ... def utcoffset(self, dt): return timedelta(minutes=-399)
> > ...
> >>>> datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ')
> > '2002-12-25 00:00:00-06:39'
>
> > and I've also figured out:
> >>>> datetime.datetime.fromtimestamp(time.time()).isoformat()[:-3]
> > '2008-01-23T11:22:54.130'
>
> > But can't figure out how to fit them together.
>
> There is nothing there to 'fit together' - in the first example given,
> the datetime object has no time component specified, so it fills in
> default vaules of zero. The following should make this clear:
>
> >>> your_time = datetime(2008, 2, 29, 15, 30, 11, tzinfo=TZ())
> >>> print your_time
> 2008-02-29 15:30:11-05:00
> >>> print your_time.isoformat('T')
> 2008-02-29T15:30:11-05:00
>
> If you wish to append the NAME of the tzinfo object instead of its
> offset, that requires a bit more playing around (along with a properly
> defined tzinfo object - check out dateutil or pytz for a concrete
> implementation of tzinfo subclasses (i.e. timezones)), but the
> following would work:
>
> >>> print your_time.strftime('%Y-%m-%dT%H:%M:%S %Z')
> 2008-02-29T15:30:11 EST
>
> For details on how the .strftime method works, see Python Standard
> Library, Section 14.2.
>
> I hope this helps!
>
> Nick Fabry
>
> > Thank you,
> > Nik
> > --
> >http://mail.python.org/mailman/listinfo/p...

>

nikbaer

1/29/2008 7:07:00 PM

On Jan 29, 10:56 am, nik <nikb...@gmail.com> wrote:
> Thanks,
> that does help and now I have:
>
> >>> from datetime import datetime, tzinfo, timedelta
> >>> import time
> >>> class TZ(tzinfo):
>
> ... def utcoffset(self,dt): return timedelta(seconds=time.timezone)
> ...>>> print datetime(2008,2,29,15,30,11,tzinfo=TZ()).isoformat()
>
> 2008-02-29T15:30:11+8:00
>
> But what I want to know now it how to get the actual time into the
> expression instead of typing the 2008,2,29,15....
> So something like: >>> print
> datetime(time.gmtime(),tzinfo=TZ()).isoformat(), but that doesn't
> work.
>
> I realize that I could do:
>
> >>> t = time.localtime()
> >>> print datetime(t[0],t[1],t[2],t[3],t[4],t[5],tzinfo=TZ()).isoformat()
>
> but I imagine there might be a cleaner way of doing this.
>
> Thanks,
> Nik
>
> On Jan 28, 9:10 pm, "Nicholas F. Fabry" <nick.fa...@coredump.us>
> wrote:
>
> > Hello, nik.
>
> > On Jan 28, 2008, at 21:03, nik wrote:
>
> > > Hi,
>
> > > How does one express the time in ISO format with the timezone
> > > designator?
>
> > > what I want is YYYY-MM-DDThh:mm:ss.sTZD
>
> > >> From the documentation I see:
> > >>>> from datetime import tzinfo, timedelta, datetime
> > >>>> class TZ(tzinfo):
> > > ... def utcoffset(self, dt): return timedelta(minutes=-399)
> > > ...
> > >>>> datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ')
> > > '2002-12-25 00:00:00-06:39'
>
> > > and I've also figured out:
> > >>>> datetime.datetime.fromtimestamp(time.time()).isoformat()[:-3]
> > > '2008-01-23T11:22:54.130'
>
> > > But can't figure out how to fit them together.
>
> > There is nothing there to 'fit together' - in the first example given,
> > the datetime object has no time component specified, so it fills in
> > default vaules of zero. The following should make this clear:
>
> > >>> your_time = datetime(2008, 2, 29, 15, 30, 11, tzinfo=TZ())
> > >>> print your_time
> > 2008-02-29 15:30:11-05:00
> > >>> print your_time.isoformat('T')
> > 2008-02-29T15:30:11-05:00
>
> > If you wish to append the NAME of the tzinfo object instead of its
> > offset, that requires a bit more playing around (along with a properly
> > defined tzinfo object - check out dateutil or pytz for a concrete
> > implementation of tzinfo subclasses (i.e. timezones)), but the
> > following would work:
>
> > >>> print your_time.strftime('%Y-%m-%dT%H:%M:%S %Z')
> > 2008-02-29T15:30:11 EST
>
> > For details on how the .strftime method works, see Python Standard
> > Library, Section 14.2.
>
> > I hope this helps!
>
> > Nick Fabry
>
> > > Thank you,
> > > Nik
> > > --
> > >http://mail.python.org/mailman/listinfo/p...

Gabriel Genellina

1/29/2008 10:50:00 PM

En Tue, 29 Jan 2008 16:56:18 -0200, nik <nikbaer@gmail.com> escribiï¿½:

>>>> print datetime(2008,2,29,15,30,11,tzinfo=TZ()).isoformat()
> 2008-02-29T15:30:11+8:00
>
> But what I want to know now it how to get the actual time into the
> expression instead of typing the 2008,2,29,15....
> So something like: >>> print
> datetime(time.gmtime(),tzinfo=TZ()).isoformat(), but that doesn't
> work.

Are you looking for datetime.now()?

--
Gabriel Genellina

Nicholas F. Fabry

1/30/2008 4:50:00 AM

On Jan 29, 2008, at 13:56, nik wrote:

> Thanks,
> that does help and now I have:
>
>>>> from datetime import datetime, tzinfo, timedelta
>>>> import time
>>>> class TZ(tzinfo):
> ... def utcoffset(self,dt): return timedelta(seconds=time.timezone)
> ...
>>>> print datetime(2008,2,29,15,30,11,tzinfo=TZ()).isoformat()
> 2008-02-29T15:30:11+8:00
>
>
> But what I want to know now it how to get the actual time into the
> expression instead of typing the 2008,2,29,15....
> So something like: >>> print
> datetime(time.gmtime(),tzinfo=TZ()).isoformat(), but that doesn't
> work.
>
> I realize that I could do:
>>>> t = time.gmtime()
>>>> print
>>>> datetime(t[0],t[1],t[2],t[3],t[4],t[5],tzinfo=TZ()).isoformat()
>
> but I imagine there might be a cleaner way of doing this.
>
> Thanks,
> Nik
>

No need for the ugliness! The constructor for class datetime has a
method, .now() that returns the current date and time, as a naive
datetime object (i.e. no tzinfo attached). Since you want an aware
datetime object (one with a tzinfo object attached), you can do it
simply by feeding .now the tzinfo object you want attached, as below:

>>> print datetime.now(TZ()).isoformat('T')
2008-01-29T23:43:16.809049-05:00

See PSL, Sect. 5.1.4

Dates and Times are a bit ugly in Python. Don't be discouraged, but
you do need to understand them quite well to get bug-free code that
plays with them.

Nick Fabry

>
> On Jan 28, 9:10 pm, "Nicholas F. Fabry" <nick.fa...@coredump.us>
> wrote:
>> Hello, nik.
>>
>> On Jan 28, 2008, at 21:03, nik wrote:
>>
>>
>>
>>> Hi,
>>
>>> How does one express the time in ISO format with the timezone
>>> designator?
>>
>>> what I want is YYYY-MM-DDThh:mm:ss.sTZD
>>
>>>> From the documentation I see:
>>>>>> from datetime import tzinfo, timedelta, datetime
>>>>>> class TZ(tzinfo):
>>> ... def utcoffset(self, dt): return timedelta(minutes=-399)
>>> ...
>>>>>> datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ')
>>> '2002-12-25 00:00:00-06:39'
>>
>>> and I've also figured out:
>>>>>> datetime.datetime.fromtimestamp(time.time()).isoformat()[:-3]
>>> '2008-01-23T11:22:54.130'
>>
>>> But can't figure out how to fit them together.
>>
>> There is nothing there to 'fit together' - in the first example
>> given,
>> the datetime object has no time component specified, so it fills in
>> default vaules of zero. The following should make this clear:
>>
>>>>> your_time = datetime(2008, 2, 29, 15, 30, 11, tzinfo=TZ())
>>>>> print your_time
>> 2008-02-29 15:30:11-05:00
>>>>> print your_time.isoformat('T')
>> 2008-02-29T15:30:11-05:00
>>
>> If you wish to append the NAME of the tzinfo object instead of its
>> offset, that requires a bit more playing around (along with a
>> properly
>> defined tzinfo object - check out dateutil or pytz for a concrete
>> implementation of tzinfo subclasses (i.e. timezones)), but the
>> following would work:
>>
>>>>> print your_time.strftime('%Y-%m-%dT%H:%M:%S %Z')
>> 2008-02-29T15:30:11 EST
>>
>> For details on how the .strftime method works, see Python Standard
>> Library, Section 14.2.
>>
>> I hope this helps!
>>
>> Nick Fabry
>>
>>> Thank you,
>>> Nik
>>> --
>>> http://mail.python.org/mailman/listinfo/p...
>
>>
> --
> http://mail.python.org/mailman/listinfo/p...

Ben Finney

1/30/2008 5:33:00 AM

"Nicholas F. Fabry" <nick.fabry@coredump.us> writes:

> The constructor for class datetime has a method, .now() that returns
> the current date and time, as a naive datetime object (i.e. no
> tzinfo attached).

It's not "the constructor for class 'datetime'" that has that method;
rather, the class 'datetime' has that method.

(If anything is "the constructor for class 'datetime'", it's the
'__new__' method -- or, some might argue, the '__init__' method -- and
that doesn't fit what you say above.)

> Dates and Times are a bit ugly in Python. Don't be discouraged, but
> you do need to understand them quite well to get bug-free code that
> plays with them.

This is unfortunately true. Native datetime support is improving, but
slowly.

--
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Ben Finney

comp.lang.python

ISO with timezone

nikbaer

Nicholas F. Fabry

nikbaer

nikbaer

Gabriel Genellina

Nicholas F. Fabry

Ben Finney

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