I am creating a naive datetime object which contains no timezone information, but I know that it is always in UTC. I want to calculate the time difference between local time and UTC for any timezone I define, which would take into account DST as well.
What I am thus doing is the following:
from datetime import datetime, timedelta
now = datetime(2018,3,27,15,20) #Create a naive datetime object
now_utc = timezone("UTC").localize(now) # Add UTC timezone information to it
now_madrid = now_utc.astimezone(timezone("Europe/Madrid")) # convert to Madrid timezone
Normally, if I was to calculate the time difference between two datetime objects I would subtract them. But when I try diff = now_utc - now_madrid , the result is the following:
In [275]: now_utc-now_madrid
Out[275]: datetime.timedelta(0)
Can anyone please tell me, how I could find the timezone difference in this case? Thank you in advance :)
Time delta is "0" because Madrid is 2 hours head of UTC.
now_utc-now_madrid
When you subtract it like this means it's in another timezone behind UTC.
There maybe a more efficient methods out there but this is how I would do it.
>>> import pytz
>>> import datetime
>>> utc_now = pytz.utc.localize(datetime.datetime.utcnow ())
>>> utc_now
datetime.datetime(2018, 3, 27, 19, 11, 19, 659257, tzinfo=<UTC>)
>>> madrid_now = utc_now.astimezone(pytz.timezone ('Europe/Madrid'))
>>> madrid_now
datetime.datetime(2018, 3, 27, 21, 11, 19, 659257, tzinfo=<DstTzInfo 'Europe/Madrid' CEST+2:00:00 DST>)
As you can see, the timezone conversion is already provided by tzinfo CEST+2:00:00 DST.
If you need to do any arithmetic on that value then try:
>>> utc_now + timedelta (hours = 2) # Since Madrid is +2:00:00 hours
datetime.datetime(2018, 3, 27, 21, 11, 19, 659257, tzinfo=<UTC>)
Or extract the offset timezone differences from strftime.
>>> madrid_now.strftime ('%z')
'+0200'
You can find more reading here: http://pytz.sourceforge.net/