Unable to convert datetime to timestamp before the year 1970

Question

I'm trying to convert the datetime object to timestamp so that I can save the time stamp to a json file and later I can convert that timestamp to datetime object.

This worked fine until I set the year greater than 1970, But when decreased the year an exception got raised saying OSError: [Errno 22] Invalid argument

import datetime
cd = datetime.datetime.strptime("1965-12-25", "%Y-%m-%d")
datetime.datetime.timestamp(cd) # this line gives error

Traceback (most recent call last):
  File "<stdin>", line 3, in <module>
OSError: [Errno 22] Invalid argument

I'm using windows 10 OS. Is there any exception or other way to convert the datetime to timestamp?

The timestamp 0 (or 1) is on the 1st of January 1970, 00:00:00, then timestamp doesn't really exists before this date — Metapod, Aug 03 '20 at 10:19
@Christophe You can use negative offsets from that date to denote prior dates… — deceze, Aug 03 '20 at 10:19
Sunil, you should really use `cd.timestamp()` instead of `datetime.datetime.timestamp(cd)`, but that just as an aside… — deceze, Aug 03 '20 at 10:20
from the [time module's docs](https://docs.python.org/3/library/time.html): "*The functions in this module may not handle dates and times before the epoch or far in the future*" — FObersteiner, Aug 03 '20 at 10:22
@deceze I did tried that.. But that gives same exception And how can I use offset? — Sunil Kumar Nerella, Aug 03 '20 at 10:22

score 1 · Accepted Answer · answered Aug 03 '20 at 10:27

you could calculate the negative timestamp as a timedelta from the epoch (1970-1-1):

import datetime
cd = datetime.datetime.strptime("1965-12-25", "%Y-%m-%d")

ts = (cd-datetime.datetime(1970,1,1)).total_seconds()

print(ts)
>>> -126835200.0

...and the other way round would be something like

dt = datetime.datetime(1970, 1, 1) + datetime.timedelta(seconds=ts)
print(dt)
>>> 1965-12-25 00:00:00

Unable to convert datetime to timestamp before the year 1970

1 Answers1