How to subtract datetimes / timestamps in python

Question

Seems like this should be so simple but for the life of me, I can't find the answer. I pull two datetimes/timestamps from the database:

2015-08-10 19:33:27.653
2015-08-10 19:31:28.209

How do I subtract the first from the second, preferably the result being in milliseconds? And yes, I have the date in there, too, because I need it to work at around midnight, as well.

Answer 1

Parse your strings as datetime.datetime objects and subtract them:

from datetime import datetime

d1 = datetime.strptime("2015-08-10 19:33:27.653", "%Y-%m-%d %H:%M:%S.%f")
d2 = datetime.strptime("2015-08-10 19:31:28.209", "%Y-%m-%d %H:%M:%S.%f")

print(d1 - d2)

Gives me:

0:01:59.444000

Also check out timedelta documentation for all possible operations.

Answer 2

you can do subtraction on 2 datetime objects to get the difference

>>> import time
>>> import datetime
>>>
>>> earlier = datetime.datetime.now()
>>> time.sleep(10)
>>> now = datetime.datetime.now()
>>>
>>> diff = now - earlier
>>> diff.seconds
10

convert your strings to datetime objects with time.strptime

datetime.strptime("2015-08-10 19:33:27.653", "%Y-%m-%d %H:%M:%S.%f")