CODEWITHSUNDEEP
pythondatetimetimetimestamp
roymaztang
roymaztang

Reputation: 65

Incorrect results of converting between python datetime and timestamp

The output of following code is totally wrong:

import time
from datetime import datetime

def sec_to_date(sec, format="%m/%d/%Y %H:%M:%S"):
    tmp = datetime.fromtimestamp(sec)
    fmtdate = tmp.strftime(format)
    return fmtdate

def date_to_sec(fmtdate, format="%m/%d/%Y %H:%M:%S"):
    t_tuple = time.strptime(fmtdate, format)
    sec = time.mktime(t_tuple)
    return sec

if __name__ == "__main__":
    fmtdate = sec_to_date(1380204000)
    print "1380204000 sec to date " + fmtdate
    fmtdate = sec_to_date(1388355120)
    print "1388355120 sec to date " + fmtdate
    sec = date_to_sec("09/26/2013 10:00:00")
    print "09/26/2013 10:00:00 to " + str(sec) + " sec"
    sec = date_to_sec("12/29/2013 17:12:00")
    print "12/29/2013 17:12:00 to " + str(sec) + " sec"

Here is the output:

1380204000 sec to date 09/26/2013 10:00:00
1388355120 sec to date 12/29/2013 17:12:00
09/26/2013 10:00:00 to 1380204000.0 sec
12/29/2013 17:12:00 to 1388355120.0 sec

The difference between two timestamps, 1380204000 and 1388355120, should be 94 days and 8.2 hours, while my results show a difference of 94 days and 7.2 hours. Any idea what happened?

Upvotes: 0

Views: 320

Answers (1)

Cyphase
Cyphase

Reputation: 12002

Your issue is Daylight Saving Time. The time between the timestamps is indeed 94 days, 8.2 hours; but given DST, that means the formatted hour of the later time will be an hour behind where you expect.

Upvotes: 2

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