Converting Datetime Objects to Seconds in Python

When working with datetime objects in Python, it often becomes necessary to convert them to seconds for various analytical purposes. However, the toordinal() method might not provide the desired output, as it only differentiates between dates with distinct days.

To accurately convert a datetime object to seconds, particularly for the specific date of January 1, 1970, there are multiple options available. For all other starting dates, you'll need to calculate the time difference between the two dates.

For January 1, 1970:

1. datetime.datetime.timestamp(): This method directly returns the number of seconds since the Unix epoch, which corresponds to 00:00:00 UTC on January 1, 1970.

   t = datetime.datetime(1970, 1, 1)
   seconds = t.timestamp()

2. time.mktime(): The time.mktime() function can also be used to convert a datetime object to seconds since the Unix epoch.

   import time
   t = datetime.datetime(1970, 1, 1)
   time_struct = t.timetuple()
   seconds = time.mktime(time_struct)

For any other starting date:

1. timedelta.total_seconds(): Subtracting two datetime objects results in a timedelta object. The total_seconds() method of timedelta provides the number of seconds between the two dates.

   t = datetime.datetime(2009, 10, 21, 0, 0)
   starting_date = datetime.datetime(1970, 1, 1)
   seconds = (t - starting_date).total_seconds()

It's important to note that the starting date should be specified in UTC (Coordinated Universal Time) for accurate results. If your datetime is not in UTC, you'll need to convert it or attach a tzinfo class with the appropriate offset.