Python: Converting string to timestamp with microseconds

Question

I would like to convert string date format to timestamp with microseconds I try the following but not giving expected result:

"""input string date -> 2014-08-01 04:41:52,117
expected result -> 1410748201.117"""

import time
import datetime

myDate = "2014-08-01 04:41:52,117"
timestamp = time.mktime(datetime.datetime.strptime(myDate, "%Y-%m-%d %H:%M:%S,%f").timetuple())

print timestamp
> 1410748201.0

Where did the milliseconds go?

Answer 1

In Python 3.4 and later you can use

timestamp = datetime.datetime.strptime(myDate, "%Y-%m-%d %H:%M:%S,%f").timestamp()

This doesn't require importing the time module. It also uses less steps so it should be faster. For older versions of python the other provided answers are probably your best option.

However, the resulting timestamp will interpret myDate in local time, rather than UTC, which may cause issues if myDate was given in UTC

Answer 2

There is no slot for the microseconds component in a time tuple:

>>> import time
>>> import datetime
>>> myDate = "2014-08-01 04:41:52,117"
>>> datetime.datetime.strptime(myDate, "%Y-%m-%d %H:%M:%S,%f").timetuple()
time.struct_time(tm_year=2014, tm_mon=8, tm_mday=1, tm_hour=4, tm_min=41, tm_sec=52, tm_wday=4, tm_yday=213, tm_isdst=-1)

You'll have to add those manually:

>>> dt = datetime.datetime.strptime(myDate, "%Y-%m-%d %H:%M:%S,%f")
>>> time.mktime(dt.timetuple()) + (dt.microsecond / 1000000.0)
1406864512.117

The other method you could follow is to produce a timedelta() object relative to the epoch, then get the timestamp with the timedelta.total_seconds() method:

epoch = datetime.datetime.fromtimestamp(0)
(dt - epoch).total_seconds()

The use of a local time epoch is quite deliberate since you have a naive (not timezone-aware) datetime value. This method can be inaccurate based on the history of your local timezone however, see J.F. Sebastian's comment. You'd have to convert the naive datetime value to a timezone-aware datetime value first using your local timezone before subtracting a timezone-aware epoch.

As such, it is easier to stick to the timetuple() + microseconds approach.

Demo:

>>> dt = datetime.datetime.strptime(myDate, "%Y-%m-%d %H:%M:%S,%f")
>>> epoch = datetime.datetime.fromtimestamp(0)
>>> (dt - epoch).total_seconds()
1406864512.117