Python3 datetime module strange behavior

Question

I came across a strange behavior of the datetime module of Python3: I calculate the difference between the dates "date" and "mon", and then add to the "date" first the resulting difference as it is, and then add to the "date" the resulting difference converted into seconds. But for some reason, the dates are different, although they should be the same. Please tell me what I'm doing wrong.

date=datetime.datetime(2021,9,4,13,00)
mon=datetime.datetime(2021, 9, 6, 0, 0)
delta=mon-date
print(date+delta)
print(date+datetime.timedelta(seconds=(delta).seconds))

result:

2021-09-06 00:00:00

2021-09-05 00:00:00

@don'ttalkjustcode I read it again, `total_seconds` is required — U13-Forward, Sep 12 '21 at 10:02
@U12-Forward, in this question the problem is they use `seconds`, instead of `total_seconds()` — buran, Sep 12 '21 at 10:02
Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. — Community, Sep 18 '21 at 11:11

buran · Answer 1 · 2021-09-12T10:07:08.923

datetime.timedelta.seconds attribute does not represent the total number of seconds in the period. There is datetime.timedelta.total_seconds() method for for that.

import datetime
date=datetime.datetime(2021,9,4,13,00)
mon=datetime.datetime(2021, 9, 6, 0, 0)
delta=mon-date
print(delta, delta.seconds)
print(delta == datetime.timedelta(seconds=delta.seconds))
print(date+delta)
print(date+datetime.timedelta(seconds=delta.total_seconds()))

output

1 day, 11:00:00 39600
False
2021-09-06 00:00:00
2021-09-06 00:00:00

As stated in the docs the timedelta.seconds attribute is seconds between 0 and 86399 inclusive.

Python3 datetime module strange behavior

1 Answers1