Parsing string to datetime with drop milliseconds

Question

I need to parse a string into a datetime with python, for example:

datetime.datetime.strptime('2018-06-29 08:15:27.243860', '%Y-%m-%d %H:%M:%S.%f')

But sometime I didn't know if the input is 2018-06-29 08:15:27.243860 or 2018-06-29 08:15:27 (without milliseconds).

If I tried

datetime.datetime.strptime('2018-06-29 08:15:27', '%Y-%m-%d %H:%M:%S.%f')

I got an exception

ValueError: time data '2018-06-29 08:15:27' does not match format '%Y-%m-%d %H:%M:%S.%f'

Is there any way to use same format to '2018-06-29 08:15:27.243860' and '2018-06-29 08:15:27'?

I don't care about milliseconds, I want to drop them.

Answer 1

use datetime.fromisoformat and replace microsecond with zero:

s = ('2018-06-29 08:15:27.243860', '2018-06-29 08:15:27')

for t in s:
    print(datetime.fromisoformat(t).replace(microsecond=0))

2018-06-29 08:15:27
2018-06-29 08:15:27

It's efficient as well.