Python - DateTime Module

DateTime Module in Python

The datetime module in Python is part of the standard library and provides classes for manipulating dates and times. With its powerful set of features, it allows you to perform various operations such as comparing dates, formatting time, arithmetic with dates, and much more. This tutorial aims to provide an in-depth guide to Python’s datetime module.

Introduction to datetime Module

Importing the Module

Before using the datetime module, you need to import it:

import datetime

Alternatively, you can import individual classes like:

from datetime import date, time, datetime, timedelta

Classes in datetime Module

The module provides several important classes:

• datetime.date
• datetime.time
• datetime.datetime
• datetime.timedelta
• datetime.tzinfo

1. The date Class

This class represents a date (year, month, and day).

from datetime import date

d = date(2025, 6, 27)
print(d)

Attributes of date

today = date.today()
print(today.year)
print(today.month)
print(today.day)

Useful Methods

print(date.today())               # Current date
print(date.fromisoformat('2025-06-27'))   # Create from ISO format
print(date.max)                  # Max date
print(date.min)                  # Min date

2. The time Class

Represents a time (hour, minute, second, microsecond).

from datetime import time

t = time(14, 30, 45)
print(t)

Attributes of time

print(t.hour)
print(t.minute)
print(t.second)
print(t.microsecond)

3. The datetime Class

This is a combination of date and time in one object.

from datetime import datetime

dt = datetime(2025, 6, 27, 14, 30, 0)
print(dt)

print(datetime.now())          # Current local date and time
print(datetime.utcnow())       # Current UTC date and time
print(datetime.today())        # Same as now()

Accessing Components

dt = datetime.now()
print(dt.year)
print(dt.month)
print(dt.day)
print(dt.hour)
print(dt.minute)
print(dt.second)

ISO Format

print(dt.isoformat())

4. The timedelta Class

Represents the difference between two datetime or date objects.

from datetime import timedelta

delta = timedelta(days=10, hours=5)
print(delta)

Arithmetic with timedelta

today = datetime.now()
future = today + timedelta(days=10)
past = today - timedelta(days=10)

print("10 days in future:", future)
print("10 days in past:", past)

Working with Date and Time

Getting Current Date and Time

now = datetime.now()
print("Now:", now)

Creating Specific DateTime

dt = datetime(2025, 6, 27, 15, 0, 0)
print("Specific:", dt)

Converting Strings to datetime

date_str = '2025-06-27 14:00:00'
dt = datetime.strptime(date_str, '%Y-%m-%d %H:%M:%S')
print(dt)

Formatting datetime Objects

now = datetime.now()
formatted = now.strftime('%Y-%m-%d %H:%M:%S')
print("Formatted:", formatted)

Common Format Codes

• %Y - Year (e.g., 2025)
• %m - Month (01 to 12)
• %d - Day (01 to 31)
• %H - Hour (00 to 23)
• %M - Minute (00 to 59)
• %S - Second (00 to 59)

Practical Use Cases

1. Countdown Timer

from datetime import datetime, timedelta

event_time = datetime(2025, 7, 1, 12, 0, 0)
now = datetime.now()
remaining = event_time - now

print("Time remaining:", remaining)

2. Age Calculator

birth_date = date(1995, 6, 27)
today = date.today()

age = today.year - birth_date.year - ((today.month, today.day) < (birth_date.month, birth_date.day))
print("Age:", age)

3. Adding Days to Date

today = date.today()
future_date = today + timedelta(days=30)
print("30 days later:", future_date)

4. Comparing Dates

d1 = date(2025, 6, 25)
d2 = date(2025, 6, 27)

print(d1 < d2)
print(d1 == d2)
print(d1 > d2)

Working with Timezones

To handle timezones, Python provides timezone and pytz (external module).

Using datetime.timezone

from datetime import datetime, timezone, timedelta

utc_dt = datetime.now(timezone.utc)
print("UTC Time:", utc_dt)

ist = timezone(timedelta(hours=5, minutes=30))
ist_dt = utc_dt.astimezone(ist)
print("IST Time:", ist_dt)

Using pytz Library

For advanced timezone support, install pytz:

pip install pytz

from datetime import datetime
import pytz

utc = pytz.utc
ist = pytz.timezone('Asia/Kolkata')

dt_utc = datetime.now(utc)
dt_ist = dt_utc.astimezone(ist)

print("UTC Time:", dt_utc)
print("IST Time:", dt_ist)

Measuring Elapsed Time

import time
from datetime import datetime

start = datetime.now()
time.sleep(2)
end = datetime.now()

elapsed = end - start
print("Elapsed Time:", elapsed)

Replacing DateTime Attributes

now = datetime.now()
new_time = now.replace(hour=18, minute=0)
print("Replaced:", new_time)

Sorting datetime List

dates = [
    datetime(2025, 6, 25),
    datetime(2025, 6, 27),
    datetime(2025, 6, 20)
]

dates.sort()
for d in dates:
    print(d)

Creating Recurring Dates

start_date = date(2025, 6, 1)
for i in range(5):
    recurring = start_date + timedelta(weeks=i)
    print(recurring)

Working with Weekdays

today = date.today()
print("Weekday (0=Mon):", today.weekday())
print("ISO Weekday (1=Mon):", today.isoweekday())

Week Number of the Year

dt = datetime(2025, 6, 27)
week_number = dt.isocalendar().week
print("Week number:", week_number)

The Python datetime module is a rich and flexible library for working with dates and times. Whether you are building calendars, timestamping data, or doing time zone conversion, datetime has got you covered. By understanding the core classes such as date, time, datetime, and timedelta, you can handle most common and complex time-related requirements in Python projects. Incorporating timezone handling via pytz further elevates your application’s capability to deal with international time standards effectively.

Mastering this module is essential for any Python developer working on real-world applications, scheduling systems, logs, analytics, or data pipelines. With a structured approach and hands-on practice, datetime can significantly simplify your temporal programming needs.