python timezone GMT conversion

Question

I have this date format:

Sat Apr 14 21:05:23 GMT-00:00 2018

I want to use datetime to store this data.

datetime.datetime.strptime(dateString, '%a %b %d %H:%M:%S %Z %Y').timetuple()

What is the date/time format for GMT? The document doesn't have GMT.

Possible duplicate of http://stackoverflow.com/questions/79797/how-do-i-convert-local-time-to-utc-in-python ? — AlG, Feb 17 '17 at 19:40
here is the link to the document:https://docs.python.org/3/library/datetime.html — CarolynCheng, Feb 17 '17 at 19:57

score 7 · Accepted Answer · answered Feb 18 '17 at 05:38

Handling timezones is always a bit confusing. In your example, you were not specific in your needs as it relates to the timezone.

Fixed timezone offset:

One way to read what you wrote is that the timezone information in your string is always GMT-00:00. If the timezone is always the same, then it is a simple matter to build a strptime string as:

dt.datetime.strptime(date, '%a %b %d %H:%M:%S GMT-00:00 %Y')

This makes no effort to interpret the timezone, since it is fixed. This will give you timezone naive datetime. And since your example immediately converted the datetime to a timetuple, I assume this is the result you wanted.

To test:

>>> date = "Sat Apr 14 21:05:23 GMT-00:00 2018"
>>> print(dt.datetime.strptime(date, '%a %b %d %H:%M:%S GMT-00:00 %Y'))
2018-04-14 21:05:23

Interpreting the timezone offset:

If you have non-GMT timezones in your timestamps, and want to preserve the information you can do:

def convert_to_datetime(datetime_string):
    # split on spaces
    ts = datetime_string.split()

    # remove the timezone
    tz = ts.pop(4)

    # parse the timezone to minutes and seconds
    tz_offset = int(tz[-6] + str(int(tz[-5:-3]) * 60 + int(tz[-2:])))

    # return a datetime that is offset
    return dt.datetime.strptime(' '.join(ts), '%a %b %d %H:%M:%S %Y') - \
        dt.timedelta(minutes=tz_offset)

This function will take your time string and make use of the UTC offset. (eg. -00:00). It will parse the timezone information out of the string and then add the resulting minutes and seconds back into the datetime to make it UTC relative.

To test:

>>> print(convert_to_datetime("Sat Apr 14 21:05:23 GMT-00:00 2018"))
2018-04-14 21:05:23

>>> print(convert_to_datetime("Sat Apr 14 21:05:23 PST-08:00 2018"))
2018-04-15 05:05:23

Timezone aware:

The above codes return a UTC relative timezone naive datetime. It if you need a timezone aware datetime, then you can do that with:

datetime.replace(tzinfo=pytz.UTC))

To test:

>>> import pytz
>>> print(convert_to_datetime("Sat Apr 14 21:05:23 GMT-00:00 2018").replace(tzinfo=pytz.UTC))
2018-04-14 21:05:23+00:00

In my case, looks like I always have GMT-00:00. Thank you so much for the answer. My problem is solved. — CarolynCheng, Feb 22 '17 at 23:09

python timezone GMT conversion

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