Working with Date and Time in Python

Time is one of the most important concepts in programming. Like a skilled clockmaker who understands every movement of the mechanism, a programmer must be able to work with different time formats, account for time zones, and precisely plan events. Python provides powerful tools for working with date and time that will help you create reliable applications. ⏰

What are date and time in programming?

Date and time in programming are ways to represent and manipulate temporal data, including the current moment, specific dates, time intervals, and their transformations.

In Python, working with date and time is mainly done through the built-in datetime module, which provides classes and functions for:

1. Representing moments in time — specific dates and times
2. Working with intervals — time periods between events
3. Formatting and parsing — conversion between strings and time objects
4. Arithmetic operations — addition, subtraction of time periods

The datetime module

The datetime module is the main tool for working with date and time in Python. It contains several important classes:

The datetime class

The most used class for working with a specific moment in time:

Python 3.13
>>> from datetime import datetime

# Getting current date and time
>>> now = datetime.now()
>>> print(f"Now: {now}")
Now: 2024-01-15 14:30:25.123456

# Creating a specific date
>>> specific_date = datetime(2024, 12, 31, 23, 59, 59)
>>> print(f"New Year: {specific_date}")
New Year: 2024-12-31 23:59:59

# Getting individual components
>>> print(f"Year: {now.year}")
Year: 2024
>>> print(f"Month: {now.month}")
Month: 1
>>> print(f"Day: {now.day}")
Day: 15
>>> print(f"Hour: {now.hour}")
Hour: 14
>>> print(f"Minute: {now.minute}")
Minute: 30

The date class

For working with dates only (without time):

Python 3.13
>>> from datetime import date

# Getting current date
>>> today = date.today()
>>> print(f"Today: {today}")
Today: 2024-01-15

# Creating a specific date
>>> birthday = date(1990, 5, 15)
>>> print(f"Birthday: {birthday}")
Birthday: 1990-05-15

# Getting day of week (0 = Monday, 6 = Sunday)
>>> print(f"Day of week: {today.weekday()}")
Day of week: 0

The time class

For working with time only (without date):

Python 3.13
>>> from datetime import time

# Creating time
>>> meeting_time = time(14, 30, 0)  # 14:30:00
>>> print(f"Meeting time: {meeting_time}")
Meeting time: 14:30:00

Formatting date and time

The strftime() method

Converting time objects to strings using formatting directives:

Python 3.13
>>> from datetime import datetime

>>> now = datetime.now()

# Various formats
>>> print(now.strftime("%Y-%m-%d"))
2024-01-15
>>> print(now.strftime("%d.%m.%Y"))
15.01.2024
>>> print(now.strftime("%A, %d %B %Y"))
Monday, 15 January 2024
>>> print(now.strftime("%d/%m/%Y %H:%M"))
15/01/2024 14:30

Main formatting directives:

The strptime() method

Parsing strings into time objects:

Python 3.13
>>> from datetime import datetime

# Parsing various formats
>>> date1 = datetime.strptime("2024-01-15", "%Y-%m-%d")
>>> print(f"Date 1: {date1}")
Date 1: 2024-01-15 00:00:00

>>> date2 = datetime.strptime("15/01/2024 14:30", "%d/%m/%Y %H:%M")
>>> print(f"Date 2: {date2}")
Date 2: 2024-01-15 14:30:00

Arithmetic operations with dates

The timedelta class

Represents a duration — the difference between two moments:

Python 3.13
>>> from datetime import datetime, timedelta

>>> now = datetime.now()
>>> print(f"Now: {now}")
Now: 2024-01-15 14:30:25.123456

# Adding time
>>> future = now + timedelta(days=7)
>>> print(f"In a week: {future}")
In a week: 2024-01-22 14:30:25.123456

# Difference between dates
>>> birthday = datetime(2024, 5, 15)
>>> time_until_birthday = birthday - now
>>> print(f"Days until birthday: {time_until_birthday.days} days")
Days until birthday: 120 days

Working with time zones

A time zone is a region on Earth where the same standard time is used. The world is divided into 24 time zones, each differing from the next by one hour.

Time zones are important when working with users from different countries or when planning events. Without considering them, problems with meeting times and data processing may occur.

Basic time zone operations

Python 3.13
>>> from datetime import datetime, timezone, timedelta

# UTC
>>> utc_now = datetime.now(timezone.utc)
>>> print(f"UTC: {utc_now}")
UTC: 2024-01-15 11:30:25.123456+00:00

# Creating a custom time zone
>>> moscow_tz = timezone(timedelta(hours=3))
>>> moscow_time = utc_now.astimezone(moscow_tz)
>>> print(f"Moscow: {moscow_time}")
Moscow: 2024-01-15 14:30:25.123456+03:00

The time module

Additional time functionality:

Python 3.13
>>> import time

# Current time in seconds since Unix epoch (January 1, 1970)
>>> timestamp = time.time()
>>> print(f"Timestamp: {timestamp}")
Timestamp: 1705319425.123456

# Execution delay
>>> print("Start")
>>> time.sleep(1)  # Pause for 1 second
>>> print("1 second passed")
Start
1 second passed

Understanding check

Which class from the datetime module is used to represent a time interval?

Conclusion

Working with date and time is a fundamental skill in programming. Python provides rich capabilities through the datetime and time modules, allowing elegant solutions from simple formatting to complex calculations with time zones.