Python 日期时间转换为时间戳

Question

I am struggling to understand why the following lines of code

from datetime import datetime 

t1 = datetime(2019, 3, 31, 0, 0, 0).timestamp()
t2 = datetime(2019, 4, 1, 0, 0, 0).timestamp()
dt = t2-t1
print(f"dt = {dt} seconds.")

output

dt = 82800.0 seconds.

instead of

dt = 86400.0 seconds.

The time difference between t2 and t1 is clearly 1 day = 24 hours = 1440 minutes = 86400 seconds. Why does this happen?

Answer 1

那是您所在时区的那一天，时钟向前更改一小时，因为 82,000 是 23 x 60 x 60

Answer 2

calling eg datetime(2019, 3, 31, 0, 0, 0).timestamp() will give you a timestamp that is localized to your machine's timezone since the datetime object is not aware of any timezone ("naive"; see the docs ). Apparently, you are in a timezone with a DST change on that date.

If you set the timezone to UTC for example (no DST), you will get the expected result:

from datetime import datetime, timezone
t1 = datetime(2019, 3, 31, 0, 0, 0, tzinfo=timezone.utc).timestamp()
t2 = datetime(2019, 4, 1, 0, 0, 0, tzinfo=timezone.utc).timestamp()
dt = t2-t1

print(f"dt = {dt} seconds.")
# dt = 86400.0 seconds.