Convert date to timestamp in Python

Question

I have a database containing dates formatted like: "2015-10-20 22:24:46". I need to convert these dates to UNIX timestamps (UTC), what's the easiest way to do it with Python?

Answer 1

import time
timestamp = time.mktime(time.strptime('2015-10-20 22:24:46', '%Y-%m-%d %H:%M:%S'))

For more on the format string with all the % symbols, see python's time library.

Answer 2

Without using any 3rd party libraries:

The most straightforward way would be to create a datetime object from the given date object and then get a timestamp from it.

from datetime import datetime

dt = datetime(
    year=d.year,
    month=d.month,
    day=d.day,
)

timestamp = int(dt.timestamp())

Answer 3

datetime.datetime.timestamp() has been added in python 3.3. It returns a float (decimals are for the milliseconds), so you must convert it to an integer yourself.

Example use:

from datetime import datetime


def ymdhms_to_timestamp(value: str) -> int:
    dt = datetime.strptime(value, "%Y-%m-%d %H:%M:%S")
    return int(dt.timestamp())


t = ymdhms_to_timestamp("2015-10-20 22:24:46")
# 1445372686
datetime.fromtimestamp(t)
# datetime.datetime(2015, 10, 20, 22, 24, 46)

Also note that since the formatted date string contains no timezone information, the resulting timestamp will not be UTC if the timezone of the system where the code executes is not. (More generally, if the stored dates were not in the same timezone as your system, the result will be incorrect.)

But if the stored formatted dates were initially UTC, you can rectify the "naive datetime" into a "timezone aware datetime" before converting it to a timestamp.

Example:

from datetime import datetime, timezone


def ymdhms_to_timestamp_utc(value: str) -> int:
    naive_dt = datetime.strptime(value, "%Y-%m-%d %H:%M:%S")
    utc_dt = naive_dt.replace(tzinfo=timezone.utc)
    return int(utc_dt.timestamp())


t = ymdhms_to_timestamp_utc("2015-10-20 22:24:46")
# 1445379886
datetime.fromtimestamp(t)
# datetime.datetime(2015, 10, 21, 0, 24, 46)

Answer 4

from datetime import datetime
import time

dt = datetime.strptime('2015-10-20 22:24:46', '%Y-%m-%d %H:%M:%S')
ts = time.mktime(dt.timetuple())