5 Best Ways to Convert Python datetime to int

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💡 Problem Formulation: In Python, one might need to convert datetime objects into integer timestamps for various purposes, such as database storage, comparison, or arithmetic operations. The input would be a Python datetime object (e.g., datetime.datetime(2023, 3, 14, 15, 9, 26)), and the desired output is an integer timestamp representing the number of seconds since the Unix epoch (e.g., 1678813766).

Method 1: Using timestamp() Method

Python’s datetime module provides the timestamp() method for datetime objects, which directly returns the time expressed as seconds since the epoch. This method requires that the datetime object is timezone-aware.

Here’s an example:

from datetime import datetime, timezone

dt = datetime(2023, 3, 14, 15, 9, 26, tzinfo=timezone.utc)
int_timestamp = int(dt.timestamp())
print(int_timestamp)

Output:

1678813766

This code snippet first creates a timezone-aware datetime object representing March 14, 2023, 15:09:26 UTC. It then converts this datetime to an integer timestamp using the timestamp() method, which counts the number of seconds from the Unix epoch, and casts the result to an integer.

Method 2: Subtracting from the Epoch

This method involves explicitly calculating the timestamp by subtracting the datetime object from the epoch time (January 1, 1970). The resulting timedelta object’s total_seconds method returns the time difference in seconds, which is then converted to an integer.

Here’s an example:

from datetime import datetime

epoch = datetime(1970, 1, 1)
dt = datetime(2023, 3, 14, 15, 9, 26)
int_timestamp = int((dt - epoch).total_seconds())
print(int_timestamp)

Output:

1678826966

In this example, we define the epoch as a datetime and subtract it from our target datetime. We then call the total_seconds() method on the resulting timedelta object and convert it to an integer to get our timestamp.

Method 3: Using calendar Module

The calendar module can be used to calculate a Unix timestamp from a datetime object. By using the timegm() function, which converts a time tuple in UTC to seconds since the epoch, we can acquire an integer timestamp.

Here’s an example:

import calendar
from datetime import datetime

dt = datetime(2023, 3, 14, 15, 9, 26)
int_timestamp = calendar.timegm(dt.utctimetuple())
print(int_timestamp)

Output:

1678826966

This snippet takes a datetime object, converts it to a UTC time tuple with utctimetuple(), and then passes it to calendar.timegm() which returns the Unix timestamp as an integer.

Method 4: Using datetime Module and Arithmetic

Another approach is to manually calculate the timestamp by converting all components of the datetime object (year, month, day, etc.) to seconds and adding them up. This method is more intricate and involves handling leap years and months with varying days.

Here’s an example:

from datetime import datetime

dt = datetime(2023, 3, 14, 15, 9, 26)
days = (dt - datetime(dt.year, 1, 1)).days
seconds = days * 86400 + dt.hour * 3600 + dt.minute * 60 + dt.second
int_timestamp = int(seconds)
print(int_timestamp)

Output:

678490166

This code first finds the number of days since the beginning of the year, converts those to seconds and then adds the seconds for the hours, minutes, and seconds of the given day. The resulting seconds are cast to an integer to represent the timestamp.

Bonus One-Liner Method 5: Using int() Directly

The simplest one-liner method would be combining the conversion to timestamp and immediate casting to an integer in one expression. It is possible if you are working with a timezone-aware datetime object.

Here’s an example:

from datetime import datetime, timezone

dt = datetime(2023, 3, 14, 15, 9, 26, tzinfo=timezone.utc)
int_timestamp = int(datetime.timestamp(dt))
print(int_timestamp)

Output:

1678813766

This single line of code effectively does what Method 1 describes but in a more compact form. It instantly converts the datetime object to a Unix timestamp as a float, and wraps the whole call with int() to convert the timestamp to an integer.

Summary/Discussion

  • Method 1: Using timestamp(). Strengths: Simple and direct. Weaknesses: Requires timezone-aware datetime objects.
  • Method 2: Subtracting from the Epoch. Strengths: Independent of timezone. Weaknesses: Less direct and more verbose.
  • Method 3: Using calendar Module. Strengths: Provides a concise way to work with UTC times. Weaknesses: Less well known, requires additional module.
  • Method 4: Using datetime Module and Arithmetic. Strengths: Gives complete control over the conversion process. Weaknesses: More error-prone, complex, and less maintainable.
  • Bonus One-Liner Method 5: Using int() Directly. Strengths: Quick and one-liner. Weaknesses: Still requires timezone-aware datetime object.