Convert to UTC Timestamp

问题:

//parses some string into that format.
datetime1 = datetime.strptime(somestring, "%Y-%m-%dT%H:%M:%S")

//gets the seconds from the above date.
timestamp1 = time.mktime(datetime1.timetuple())

//adds milliseconds to the above seconds.
timeInMillis = int(timestamp1) * 1000

How do I (at any point in that code) turn the date into UTC format? I've been ploughing through the API for what seems like a century and cannot find anything that I can get working. Can anyone help? It's currently turning it into Eastern time i believe (however I'm in GMT but want UTC).

EDIT: I gave the answer to the guy with the closest to what I finally found out.

datetime1 = datetime.strptime(somestring, someformat)
timeInSeconds = calendar.timegm(datetime1.utctimetuple())
timeInMillis = timeInSeconds * 1000

:)

回答1:

def getDateAndTime(seconds=None):
 """
  Converts seconds since the Epoch to a time tuple expressing UTC.
  When 'seconds' is not passed in, convert the current time instead.
  :Parameters:
      - `seconds`: time in seconds from the epoch.
  :Return:
      Time in UTC format.
"""
return time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime(seconds))`

This converts local time to UTC

time.mktime(time.localtime(calendar.timegm(utc_time)))

http://feihonghsu.blogspot.com/2008/02/converting-from-local-time-to-utc.html

If converting a struct_time to seconds-since-the-epoch is done using mktime, this conversion is in local timezone. There's no way to tell it to use any specific timezone, not even just UTC. The standard 'time' package always assumes that a time is in your local timezone.

回答2:

datetime.utcfromtimestamp is probably what you're looking for:

>>> timestamp1 = time.mktime(datetime.now().timetuple())
>>> timestamp1
1256049553.0
>>> datetime.utcfromtimestamp(timestamp1)
datetime.datetime(2009, 10, 20, 14, 39, 13)

回答3:

I think you can use the utcoffset() method:

utc_time = datetime1 - datetime1.utcoffset()

The docs give an example of this using the astimezone() method here.

Additionally, if you're going to be dealing with timezones, you might want to look into the PyTZ library which has lots of helpful tools for converting datetime's into various timezones (including between EST and UTC)

With PyTZ:

from datetime import datetime
import pytz

utc = pytz.utc
eastern = pytz.timezone('US/Eastern')

# Using datetime1 from the question
datetime1 = datetime.strptime(somestring, "%Y-%m-%dT%H:%M:%S")

# First, tell Python what timezone that string was in (you said Eastern)
eastern_time = eastern.localize(datetime1)

# Then convert it from Eastern to UTC
utc_time = eastern_time.astimezone(utc)

回答4:

You probably want one of these two:

import time
import datetime

from email.Utils import formatdate

rightnow = time.time()

utc = datetime.datetime.utcfromtimestamp(rightnow)
print utc

print formatdate(rightnow) 

The two outputs look like this

2009-10-20 14:46:52.725000
Tue, 20 Oct 2009 14:46:52 -0000