timedelta problem

[Denis McMahon]

On Fri, 15 Aug 2014 10:24:47 +0800, luofeiyu wrote:

> problem :
> 
> t1 is GMT time   2014  00:36:46 t2 is GMT time   2014  14:36:46
> 
> datetime.datetime.strptime  do not give me the right answer.

As far as I can tell from running the following, it all seems to work as 
expected in python 3.2 (and hence I expect in 3.4). If the expected 
output doesn't match yours, it would be interesting to see what your 
output is. If the expected output does match yours, and you think it's 
wrong, it would be interesting to know which bits you think are wrong and 
why you think they are wrong, because having a fair bit of the night 
looking at this, it all looks good to me.

#!/usr/bin/python3

from datetime import tzinfo, timedelta, datetime, timezone

# define timedelta based timezones

UTCm7 = timezone(timedelta(0,-7*3600),"UTC-07:00")
UTCp7 = timezone(timedelta(0,+7*3600),"UTC+07:00")
UTC  = timezone(timedelta(0),        "UTC+00:00")

# some timestrings

t1 = 'Sat, 09 Aug 2014 07:36:46 -0700'
t2 = 'Sat, 09 Aug 2014 07:36:46 +0700'
t3 = 'Sat, 09 Aug 2014 07:36:46 +0000'

# make some datetime objects
# these are both utc -7

a1 = datetime.strptime(t1,"%a, %d %b %Y %H:%M:%S %z")
b1 = datetime(2014, 8, 9, 7, 36, 46, tzinfo = UTCm7)

# these are both utc +7

a2 = datetime.strptime(t2,"%a, %d %b %Y %H:%M:%S %z")
b2 = datetime(2014, 8, 9, 7, 36, 46, tzinfo = UTCp7)

# these are both utc

a3 = datetime.strptime(t3,"%a, %d %b %Y %H:%M:%S %z")
b3 = datetime(2014, 8, 9, 7, 36, 46, tzinfo = UTC)

# print them out as stored

print( "UTC -7:" )
print( t1 )
print( a1 )
print( b1 )

print( "UTC +7:" )
print( t2 )
print( a2 )
print( b2 )

print( "UTC:" )
print( t3 )
print( a3 )
print( b3 )

# print them out converted to UTC

print( "UTC -7 as UTC:" )
print( a1.astimezone( UTC ) )
print( b1.astimezone( UTC ) )

print( "UTC +7 as UTC:" )
print( a2.astimezone( UTC ) )
print( b2.astimezone( UTC ) )

print( "UTC as UTC:" )
print( a3.astimezone( UTC ) )
print( b3.astimezone( UTC ) )

# expected output

"""
UTC -7:
Sat, 09 Aug 2014 07:36:46 -0700
2014-08-09 07:36:46-07:00
2014-08-09 07:36:46-07:00
UTC +7:
Sat, 09 Aug 2014 07:36:46 +0700
2014-08-09 07:36:46+07:00
2014-08-09 07:36:46+07:00
UTC:
Sat, 09 Aug 2014 07:36:46 +0000
2014-08-09 07:36:46+00:00
2014-08-09 07:36:46+00:00
UTC -7 as UTC:
2014-08-09 14:36:46+00:00
2014-08-09 14:36:46+00:00
UTC +7 as UTC:
2014-08-09 00:36:46+00:00
2014-08-09 00:36:46+00:00
UTC as UTC:
2014-08-09 07:36:46+00:00
2014-08-09 07:36:46+00:00
"""

-- 
Denis McMahon, denismfmcmahon at gmail.com