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Rahul Gupta
Rahul Gupta

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Day 39/100: Working with datetime and calendar in Python

#python #programming #learning #100daysofcode

Welcome to Day 39 of your Python journey!
Dates and times are everywhere: scheduling tasks, logging events, timestamping data, or building calendars. Python makes this easy with two powerful modules: datetime and calendar.

Today, you’ll learn how to handle dates, times, and calendars like a pro. ⏰

📦 Importing the Modules 

import datetime
import calendar
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🕰️ 1. Getting the Current Date and Time 

from datetime import datetime

now = datetime.now()
print("Current Date & Time:", now)
print("Date:", now.date())
print("Time:", now.time())
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📌 Output: 

Current Date & Time: 2025-08-01 14:30:22.123456
Date: 2025-08-01
Time: 14:30:22.123456
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📆 2. Creating Custom Dates and Times 

from datetime import date, time

# Create a date
my_date = date(2025, 12, 25)
print("Custom Date:", my_date)

# Create a time
my_time = time(14, 30, 0)
print("Custom Time:", my_time)
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⏳ 3. Date Arithmetic (Timedelta)

You can perform addition and subtraction with timedelta.

from datetime import timedelta

today = date.today()
future = today + timedelta(days=10)
past = today - timedelta(days=30)

print("Today:", today)
print("10 days later:", future)
print("30 days ago:", past)
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🗓️ 4. Formatting and Parsing Dates

✅ Formatting with strftime(): 

print(now.strftime("%Y-%m-%d %H:%M:%S"))
print(now.strftime("%A, %B %d, %Y"))  # Friday, August 01, 2025
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✅ Parsing Strings with strptime(): 

date_str = "2025-12-31"
parsed_date = datetime.strptime(date_str, "%Y-%m-%d")
print(parsed_date)
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📜 5. Working with the calendar Module

The calendar module is perfect for generating and exploring calendar data.

✅ Printing a Month Calendar: 

import calendar

print(calendar.month(2025, 8))
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✅ Checking Leap Years: 

print(calendar.isleap(2024))  # True
print(calendar.isleap(2025))  # False
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✅ Getting a Year’s Calendar: 

print(calendar.calendar(2025))
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⏱️ 6. Measuring Time (Performance Testing)

Use datetime to measure execution time:

start = datetime.now()

# Simulate task
for _ in range(1000000):
    pass

end = datetime.now()
print("Execution Time:", end - start)
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🧠 Quick Reference for strftime Codes:

  • %Y – Year (2025)
  • %m – Month (01-12)
  • %d – Day (01-31)
  • %H – Hour (00-23)
  • %M – Minute (00-59)
  • %S – Second (00-59)
  • %A – Weekday (Monday)
  • %B – Month Name (August)

🎯 Practice Challenge

  1. Print today’s date and time in the format: Friday, 01 August 2025 - 02:30 PM
  2. Ask the user for their birthdate and calculate their age in days.
  3. Display the calendar for the current month.

🧾 Summary

  • Use datetime to handle dates, times, and timedeltas.
  • Use strftime() and strptime() for formatting and parsing.
  • Use calendar to display calendars and check leap years.

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