🔷 Introduction

Handling dates and time is essential in many real-world applications such as scheduling systems, logs, data analysis, and APIs.

Python provides a powerful built-in module called datetime to work with dates and time efficiently.

In this lesson, you will learn:

✔ How to create and manipulate dates
✔ How to format and parse date strings
✔ How to perform time calculations
✔ How to work with durations using timedelta

🟩 1. The datetime Module

🔹 Importing

from datetime import datetime

🔹 Get current date and time

now = datetime.now()
print(now)

🔹 Get only the date

print(now.date())

🔹 Get only the time

print(now.time())

🟩 2. Creating Custom Dates

from datetime import datetime

d = datetime(2025, 1, 15, 10, 30)
print(d)

✔ Format: datetime(year, month, day, hour, minute)

🟩 3. Formatting Dates (strftime)

Convert date → string:

now = datetime.now()

print(now.strftime("%Y-%m-%d"))
print(now.strftime("%d/%m/%Y"))
print(now.strftime("%H:%M:%S"))

🔹 Common format codes

🟩 4. Parsing Dates (strptime)

Convert string → date:

from datetime import datetime

date_str = "2025-01-15"
date_obj = datetime.strptime(date_str, "%Y-%m-%d")

print(date_obj)

🟩 5. Time Calculations (timedelta)

🔹 Adding time

from datetime import timedelta

now = datetime.now()
future = now + timedelta(days=7)

print(future)

🔹 Subtracting dates

past = datetime(2024, 1, 1)
diff = now - past

print(diff.days)

🟩 6. Practical Examples

🔹 Calculate age

birth = datetime(2000, 5, 10)
today = datetime.now()

age = today.year - birth.year
print("Age:", age)

🔹 Check if a date is in the future

event = datetime(2025, 12, 31)

if event > datetime.now():
    print("Event is upcoming")

🟧 7. Exercises (Hidden Solutions)

Exercise 1 — Print current date

from datetime import datetime
print(datetime.now())

Exercise 2 — Format today’s date

from datetime import datetime
print(datetime.now().strftime("%d/%m/%Y"))

Exercise 3 — Parse a date string

from datetime import datetime
d = datetime.strptime("2025-05-10", "%Y-%m-%d")
print(d)

Exercise 4 — Add 10 days to today

from datetime import datetime, timedelta
print(datetime.now() + timedelta(days=10))

Exercise 5 — Calculate difference between two dates

from datetime import datetime
d1 = datetime(2025, 1, 1)
d2 = datetime(2024, 1, 1)

print((d1 - d2).days)

🟦 Conclusion

In this lesson, you learned how to:

✔ Work with dates and time using datetime
✔ Format and parse date strings
✔ Perform time calculations
✔ Handle real-world date scenarios

These skills are widely used in:

• APIs
• Data analysis
• Logging systems
• Scheduling applications

🚀 Mini Project — Event Scheduler & Countdown App

Project idea

Build a Python program that lets the user:

• enter an event name
• enter an event date
• calculate how many days remain until the event
• show whether the event is in the future, today, or already passed

This project is perfect for practicing:

• datetime
• strptime()
• strftime()
• date comparison
• timedelta

🧩 What the app does

Example:

Enter event name: Python Exam
Enter event date (YYYY-MM-DD): 2026-12-20

Output:

Event: Python Exam
Date: 20/12/2026
Days remaining: 45

If the date is today:

The event is today!

If the date is in the past:

This event has already passed.

✅ Full Solution

from datetime import datetime

event_name = input("Enter event name: ")
event_date_str = input("Enter event date (YYYY-MM-DD): ")

try:
    event_date = datetime.strptime(event_date_str, "%Y-%m-%d").date()
    today = datetime.now().date()

    difference = event_date - today
    days_left = difference.days

    print("\nEvent:", event_name)
    print("Date:", event_date.strftime("%d/%m/%Y"))

    if days_left > 0:
        print("Days remaining:", days_left)
    elif days_left == 0:
        print("The event is today!")
    else:
        print("This event has already passed.")

except ValueError:
    print("Invalid date format. Please use YYYY-MM-DD.")

event_name = input("Enter event name: ")
event_date_str = input("Enter event date (YYYY-MM-DD): ")

event_date = datetime.strptime(event_date_str, "%Y-%m-%d").date()

today = datetime.now().date()

difference = event_date - today
days_left = difference.days

🧠 Skills practiced

With this mini project, you practice:

• parsing dates with strptime()
• formatting dates with strftime()
• comparing dates
• using timedelta indirectly through date subtraction
• handling invalid input with try/except

🛠 Improved Version — Multiple Events

Here is a slightly more advanced version that stores several events in a list.

from datetime import datetime

events = []

while True:
    name = input("\nEnter event name (or type 'stop' to finish): ")
    if name.lower() == "stop":
        break

    date_str = input("Enter event date (YYYY-MM-DD): ")

    try:
        event_date = datetime.strptime(date_str, "%Y-%m-%d").date()
        events.append((name, event_date))
    except ValueError:
        print("Invalid date format. Please use YYYY-MM-DD.")

today = datetime.now().date()

print("\n=== Event Schedule ===")
for name, event_date in events:
    days_left = (event_date - today).days
    print(f"\nEvent: {name}")
    print("Date:", event_date.strftime("%d/%m/%Y"))

    if days_left > 0:
        print("Days remaining:", days_left)
    elif days_left == 0:
        print("The event is today!")
    else:
        print("This event has already passed.")

🎯 Challenge ideas

You can extend the project with:

1. sort events by nearest date
2. save events to a file
3. show only future events
4. add event time
5. create a GUI version with Tkinter
6. highlight the nearest upcoming event