Datetime Module0%
Collections Module

Datetime Module

Beginner12 min read•Updated: Jul 11, 2026
Study Materials

The Datetime Module in Python

Date and time manipulation is central to backend systems, financial transaction logs, scheduling engines, and data analytics. Python's built-in datetime module provides classes for managing calendar dates, times, durations, and timezones.

1. The Core datetime Classes

The module is structured into four primary classes:

  • date: Represents an idealized calendar date (Year, Month, Day).
  • time: Represents an idealized time of day (Hour, Minute, Second, Microsecond), independent of any date.
  • datetime: Combines both date and time into a single timestamp.
  • timedelta: Represents a duration expressing the difference between two dates or times.
Python
from datetime import date, time, datetime, timedelta, timezone
 
# 1. Date instance
today = date.today()
print(f"Today: {today.year}-{today.month:02d}-{today.day:02d}")
 
# 2. Time instance
lunch_time = time(13, 30, 0) # 01:30:00 PM
print(f"Lunch: {lunch_time}")
 
# 3. Datetime instance
now = datetime.now()
print(f"Current local timestamp: {now}")
 
# 4. Timezone-Aware UTC Timestamp (Python 3.11+ recommended)
utc_now = datetime.now(timezone.utc)
print(f"Current UTC timestamp: {utc_now}")

2. Formatting Dates with strftime()

The strftime() method (String Format Time) converts a datetime object into a custom formatted string according to format directives:

DirectiveMeaningExample Output
%Y4-digit Year2026
%m2-digit Month (01-12)09
%d2-digit Day of Month (01-31)12
%HHour in 24-hour clock (00-23)16
%IHour in 12-hour clock (01-12)04
%MMinute (00-59)15
%SSecond (00-59)30
%pAM / PMPM
%BFull Month NameSeptember
%AFull Weekday NameSaturday
Python
from datetime import datetime
 
current = datetime.now()
 
# Standard formats:
print(current.strftime("%d-%m-%Y %H:%M:%S")) # 12-09-2026 16:15:30
print(current.strftime("%A, %B %d, %Y")) # Saturday, September 12, 2026
print(current.strftime("%I:%M %p")) # 04:15 PM
print(current.isoformat()) # 2026-09-12T16:15:30.123456

3. Parsing Strings into Dates with strptime()

The strptime() method (String Parse Time) converts text strings from files, databases, or APIs into datetime objects using the corresponding format string:

Python
from datetime import datetime
 
date_str = "2026-09-12 18:45"
parsed_dt = datetime.strptime(date_str, "%Y-%m-%d %H:%M")
 
print(parsed_dt) # 2026-09-12 18:45:00
print(type(parsed_dt)) # <class 'datetime.datetime'>
print("Year:", parsed_dt.year)
Memory Trick: - strftime -> Format to string. - strptime -> Parse from string.

4. Date Arithmetic with timedelta

timedelta allows calculating deadlines, age, past dates, and future intervals effortlessly:

Python
from datetime import datetime, timedelta
 
now = datetime.now()
 
# Calculate future deadline (14 days and 4 hours ahead)
trial_duration = timedelta(days=14, hours=4)
expiry_date = now + trial_duration
print(f"Subscription expires on: {expiry_date.strftime('%Y-%m-%d %H:%M')}")
 
# Calculating difference between two dates
epoch_event = datetime(2026, 1, 1)
elapsed = now - epoch_event
print(f"Days elapsed since New Year 2026: {elapsed.days} days")
print(f"Total seconds elapsed: {elapsed.total_seconds():,.0f} s")

5. Naive vs. Aware Datetime Objects

  • Naive: Contains no timezone information. Python cannot determine what geographical timezone it belongs to.
  • Aware: Holds timezone metadata (such as UTC, IST, or EST) via the tzinfo parameter, preventing ambiguity across distributed servers.
Python
from datetime import datetime, timezone, timedelta
 
# Create timezone offset (IST: UTC + 5:30)
ist_zone = timezone(timedelta(hours=5, minutes=30), name="IST")
 
# Current time in IST
ist_time = datetime.now(ist_zone)
print(f"Time in India: {ist_time}")
# Output: 2026-09-12 16:15:30.123456+05:30

Multiple Choice Questions

1. Which method converts a datetime object into a custom formatted string?

A. datetime.strptime() B. datetime.to_string() C. datetime.strftime() D. datetime.parse() Answer: C Explanation: strftime() ("String Format Time") formats a datetime object into a string representation according to specified format directives.

2. What does strptime("25/12/2026", "%d/%m/%Y") produce?

A. A string "25-12-2026" B. A datetime object representing December 25, 2026 C. A timestamp integer D. A syntax error Answer: B Explanation: strptime() parses a string into a Python datetime object according to the directive tokens provided.

3. Which class represents the elapsed duration or difference between two datetime instances?

A. datetime.duration B. datetime.timedelta C. datetime.timespan D. datetime.interval Answer: B Explanation: timedelta represents differences between two dates or times, supporting arithmetic operations like addition and subtraction.

4. What is the difference between a "naive" and an "aware" datetime object in Python?

A. Naive objects have microsecond precision, while aware objects do not B. Aware objects contain explicit timezone offset information (tzinfo), whereas naive objects do not C. Naive objects are deprecated in Python 3 D. Aware objects can only be created on Linux Answer: B Explanation: An aware datetime has an associated tzinfo indicating its geographical timezone offset; naive datetimes lack timezone context.

5. What directive in strftime() represents the 4-digit year?

A. %y B. %Y C. %YEAR D. %d Answer: B Explanation: %Y outputs the 4-digit year (e.g. 2026), whereas lowercase %y outputs the 2-digit year (e.g. 26).

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