How to convert UTC-4 to US/Eastern in python?
Question: I read time stamps from text file. These time stamps are in UTC-4. I need to
convert them to US/Eastern.

    
    
    import datetime
    datetime_utc4 = datetime.datetime.strptime("12/31/2012 16:15", "%m/%d/%Y %H:%M")
    

How do I convert it to US/Eastern? One-line answer would be best.

Note: my original question stated EST to EDT. But it does not change the
essence of the question, which is how to go from one time zone to another.
Upon some reading (following comments) I gather that python (pytz in
particular) does not treat EST and EDT as separate time zones, rather as two
flavors of US/Eastern. But this is an implementation detail. It is common to
refer to EST and EDT as two different time zones, see e.g.
[here](http://www.timeanddate.com/library/abbreviations/timezones/na/edt.html).


Answer: Based on your update and comments, I now understand that you have data that is
fixed at UTC-4 and you want to correct this so that it is valid in US Eastern
Time, including both EST/EDT where appropriate. Here is how you do that with
[pytz](http://pytz.sourceforge.net/).

    
    
    from datetime import datetime
    import pytz
    
    dt = datetime.strptime("12/31/2012 16:15", "%m/%d/%Y %H:%M") \
                 .replace(tzinfo = pytz.FixedOffset(-240)) \
                 .astimezone(pytz.timezone('America/New_York'))
    

Note that I used the `America/New_York` time zone id. This is the most correct
form of identifier. You could instead use `US/Eastern` and it would work just
fine, but be aware that this is an alias, and it is just there for backwards
compatibility.

