Time inconsistencies in Python

I am facing some problems in a cross platform program: when I open a python shell in Linux and in Windows, I don't get the same time from the Epoch.

In Linux, I tried to do dpkg-reconfigure tzdata.

Currently, in linux I get that avec the dpkg-reconfigure tzdata:

Current default time zone: 'Europe/London'
Local time is now:      Mon May 30 10:29:52 BST 2011.
Universal Time is now:  Mon May 30 09:29:52 UTC 2011.

Then, in the python console, I create this script:

import time
print time.tzname, time.timezone, time.altzone, time.daylight
print time.localtime()
print time.localtime(0)

On linux that returns:

('GMT', 'BST') 0 -3600 1
time.struct_time(tm_year=2011, tm_mon=5, tm_mday=30, tm_hour=11, tm_min=35, tm_sec=8, tm_wday=0, tm_yday=150, tm_isdst=1)
time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=1, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)

On Windows that returns:

('GMT', 'GMT (heure d\x92\xe9t\xe9)') 0 -3600 1
time.struct_time(tm_year=2011, tm_mon=5, tm_mday=30, tm_hour=11, tm_min=40, tm_sec=1, tm_wday=0, tm_yday=150, tm_isdst=1)
time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)

Then I tried this script:

myTime = 0
dst = 0
while myTime < time.time():
   l = time.localtime(myTime)
   if l[8] is not dst:
       dst = l[8]
       print dst, l
myTime += 24*60*60

The first lines returned in Linux are:

    1 time.struct_time(tm_year=1972, tm_mon=3, tm_mday=27, tm_hour=1, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=80, tm_isdst=1)
    0 time.struct_time(tm_year=1972, tm_mon=10, tm_mday=30, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=304, tm_isdst=0)
    1 time.struct_time(tm_year=1973, tm_mon=3, tm_mday=19, tm_hour=1, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=78, tm_isdst=1)
    0 time.struct_time(tm_year=1973, tm_mon=10, tm_mday=29, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=302, tm_isdst=0)
    IT CONTINUES UNTIL TODAY..................

The first lines returned in Windows are:

    1 time.struct_time(tm_year=1970, tm_mon=3, tm_mday=30, tm_hour=1, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=89, tm_isdst=1)
    0 time.struct_time(tm_year=1970, tm_mon=10, tm_mday=26, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=299, tm_isdst=0)
    1 time.struct_time(tm_year=1971, tm_mon=3, tm_mday=29, tm_hour=1, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=88, tm_isdst=1)
    0 time.struct_time(tm_year=1971, tm_mon=11, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=305, tm_isdst=0)
    1 time.struct_time(tm_year=1972, tm_mon=3, tm_mday=27, tm_hour=1, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=87, tm_isdst=1)
    0 time.struct_time(tm_year=1972, tm_mon=10, tm_mday=30, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=304, tm_isdst=0)
    1 time.struct_time(tm_year=1973, tm_mon=3, tm_mday=26, tm_hour=1, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=85, tm_isdst=1)
    0 time.struct_time(tm_year=1973, tm_mon=10, tm_mday=29, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=302, tm_isdst=0)
    IT CONTINUES UNTIL TODAY..................

So in Windows, we get the date from 1970 whereas in Linux, it starts on 1972!

Then if I write that in my bash console:

zdump -v /usr/share/zoneinfo/Europe/London | grep 197

I get that:

/usr/share/zoneinfo/Europe/London  Sun Oct 31 01:59:59 1971 UTC = Sun Oct 31 02:59:59 1971 BST isdst=0 gmtoff=3600
/usr/share/zoneinfo/Europe/London  Sun Oct 31 02:00:00 1971 UTC = Sun Oct 31 02:00:00 1971 GMT isdst=0 gmtoff=0
/usr/share/zoneinfo/Europe/London  Sun Mar 19 01:59:59 1972 UTC = Sun Mar 19 01:59:59 1972 GMT isdst=0 gmtoff=0
/usr/share/zoneinfo/Europe/London  Sun Mar 19 02:00:00 1972 UTC = Sun Mar 19 03:00:00 1972 BST isdst=1 gmtoff=3600
/usr/share/zoneinfo/Europe/London  Sun Oct 29 01:59:59 1972 UTC = Sun Oct 29 02:59:59 1972 BST isdst=1 gmtoff=3600
/usr/share/zoneinfo/Europe/London  Sun Oct 29 02:00:00 1972 UTC = Sun Oct 29 02:00:00 1972 GMT isdst=0 gmtoff=0
/usr/share/zoneinfo/Europe/London  Sun Mar 18 01:59:59 1973 UTC = Sun Mar 18 01:59:59 1973 GMT isdst=0 gmtoff=0
/usr/share/zoneinfo/Europe/London  Sun Mar 18 02:00:00 1973 UTC = Sun Mar 18 03:00:00 1973 BST isdst=1 gmtoff=3600
/usr/share/zoneinfo/Europe/London  Sun Oct 28 01:59:59 1973 UTC = Sun Oct 28 02:59:59 1973 BST isdst=1 gmtoff=3600
IT CONTINUES UNTIL 1979 !..........

As you can see, we don't see any thing for 1970!

How can I change the timezone of Debian, into my own one!?

Old message: I am facing some problems in a cross platform program: when I open a python shell in Linux and in Windows, I don't get the same time from the Epoch.

In linux (debian squeeze):

>>> import time
>>> time.localtime()
time.struct_time(tm_year=2011, tm_mon=5, tm_mday=30, tm_hour=10, tm_min=1, tm_sec=57, tm_wday=0, tm_yday=150, tm_isdst=1)
>>> time.localtime(0)
time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=1, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)

In Windows (7 64 bits Professional):

>>> import time
>>> time.localtime()
time.struct_time(tm_year=2011, tm_mon=5, tm_mday=30, tm_hour=10, tm_min=1, tm_sec=59, tm_wday=0, tm_yday=150, tm_isdst=1)
>>> time.localtime(0)
t开发者_JAVA百科ime.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)

As you can see there is an hour of difference. Why?

Thank you for your answer that is what I did then: in Windows:

>>> time.tzname
('GMT', 'GMT (heure d\x92\xe9t\xe9)')
>>> time.timezone
0
>>> time.altzone
-3600
>>> time.daylight
1

in Linux:

>>> time.tzname
('UTC', 'UTC')
>>> time.timezone
0
>>> time.altzone
0
>>> time.daylight
0

I don't want to use gmtime if I don't know why there is a problem. I tried to change the time in Linux to get the same as in Windows (I started the development of my software in Windows and it works perfectly, that's why I want to change the system time in Linux and not in windows). In Linux, I tried to do dpkg-reconfigure tzdata. But whatever I choose the time is still wrong.

Currently, in linux I get that avec the dpkg-reconfigure tzdata:

Current default time zone: 'Europe/London'
Local time is now:      Mon May 30 10:29:52 BST 2011.
Universal Time is now:  Mon May 30 09:29:52 UTC 2011.

I don't understand which time used in Windows. I am using 'UTC'.

I create this script:

import time
print time.tzname, time.timezone, time.altzone, time.daylight
print time.localtime()
print time.localtime(0)

On linux that returns:

('GMT', 'BST') 0 -3600 1
time.struct_time(tm_year=2011, tm_mon=5, tm_mday=30, tm_hour=11, tm_min=35, tm_sec=8, tm_wday=0, tm_yday=150, tm_isdst=1)
time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=1, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)

On Windows that returns:

('GMT', 'GMT (heure d\x92\xe9t\xe9)') 0 -3600 1
time.struct_time(tm_year=2011, tm_mon=5, tm_mday=30, tm_hour=11, tm_min=40, tm_sec=1, tm_wday=0, tm_yday=150, tm_isdst=1)
time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)

And as you can see, there is still the problem of time since the Epoch (it was 1 am at the epoch...)

I create another topic because it seems not to be anymore due to python: Timezone issues

Is the time or time zone set differently on either of your PCs?

http://docs.python.org/library/time.html#time.gmtime

The link above suggests using time.gmtime() to get time since the epoch in UTC, instead of local time.

This is almost certainly due to different time zone configurations between the two environments.

Examine time.tzname, time.timezone, time.altzone, time.daylight

I realise this is an old question, but I was looking at some issues in the same area and thought I would share:

From 1968-1972 The UK kept BST throughout the year

This means there were no DST changes for Europe/London in those years - so your Linux results are accurate there. There is no doubt a difference between 'GMT' and 'Europe/London', since GMT applies to all countries in that timezone not jus the UK.

See, for example: http://wwp.greenwichmeantime.co.uk/daylight-saving-time/history-william-willetts.htm