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Introduction
Python’s built-in datetime module can simply be thought-about the go-to library for dealing with date and time formatting and manipulation within the ecosystem. Most Python coders are conversant in creating datetime objects, formatting them into strings, and performing fundamental arithmetic. Nevertheless, this highly effective module, generally alongside associated libraries akin to calendar, affords a ton extra performance past the fundamentals that may remedy complicated date and time-related issues with shocking ease.
This text appears at 10 helpful — and maybe shocking — issues you possibly can accomplish with Python’s datetime module. From navigating timezones to calculating particular weekday occurrences, these examples will exhibit the flexibility of Python’s date and time toolkit.
1. Discovering the Day of the Week
Past simply understanding the date, you usually must know the day of the week. The datetime module makes this trivial. Each datetime object has a weekday() technique, which returns the day of the week as an integer (Monday is 0, Sunday is 6), and a strftime() technique, which may format the date to point out the total day title.
import datetime
# Choose a date
at the moment = datetime.date(2025, 7, 10)
# Get the day of the week (Monday is 0)
day_of_week_num = at the moment.weekday()
print(f"Day of the week (numeric): {day_of_week_num}")
# Get the total title of the day
day_name = some_date.strftime("%A")
print(f"The date {at the moment} is a {day_name}")
Output:
The date 2025-07-10 is a Thursday
2. Calculating the Time Till a Future Occasion
Ever wanted a easy countdown timer? With datetime, you possibly can simply calculate the time remaining till a selected future date and time. By subtracting the present datetime from a future one, you get a timedelta object that represents the distinction.
import datetime
# Outline a future occasion
new_year_2050 = datetime.datetime(2050, 1, 1, 0, 0, 0)
# Get the present time
now = datetime.datetime.now()
# Calculate the distinction
time_left = new_year_2050 - now
print(f"Time left till New Yr 2050: {time_left}")
Output:
Time left till New Yr 2050: 8940 days, 16:05:52.120836
3. Working with Timezones
Dealing with timezones is hard. A naive datetime object has no timezone information, whereas an conscious object does possess this information. Utilizing the pytz library (or the built-in zoneinfo in Python 3.9+) makes working with timezones manageable.
For example, you should use one timezone’s time as a base for conversion to a different timezone like this:
import datetime
from pytz import timezone
# Create a timezone-aware datetime for New York
nyc_tz = timezone('America/New_York')
nyc_time = datetime.datetime.now(nyc_tz)
print(f"New York Time: {nyc_time}")
# Convert it to a different timezone
london_tz = timezone('Europe/London')
london_time = nyc_time.astimezone(london_tz)
print(f"London Time: {london_time}")
Output:
New York Time: 2025-07-10 07:57:53.900220-04:00
London Time: 2025-07-10 12:57:53.900220+01:00
4. Getting the Final Day of a Month
Determining the final day of a month shouldn’t be simple since months have completely different numbers of days. You would write logic to deal with 30/31 days together with February (do not forget about leap years!), or you could possibly use a intelligent trick with datetime and timedelta. The technique is to seek out the primary day of the subsequent month after which subtract in the future.
import datetime
def get_last_day_of_month(12 months, month):
# Deal with month rollover for December -> January
if month == 12:
next_month_first_day = datetime.date(12 months + 1, 1, 1)
else:
next_month_first_day = datetime.date(12 months, month + 1, 1)
# Subtract in the future to get the final day of the present month
return next_month_first_day - datetime.timedelta(days=1)
# Instance: Get the final day of February 2024 (a intercalary year)
last_day = get_last_day_of_month(2024, 2)
print(f"The final day of February 2024 is: {last_day}")
Output:
The final day of February 2024 is: 2024-02-29
5. Calculating Your Exact Age
You need to use datetime to calculate somebody’s age all the way down to the day. The logic includes subtracting the birthdate from the present date after which performing a small adjustment to account for whether or not the individual’s birthday has occurred but this 12 months.
import datetime
def calculate_age(birthdate):
at the moment = datetime.date.at the moment()
age = at the moment.12 months - birthdate.12 months - ((at the moment.month, at the moment.day)
Output:
If alive at the moment, Pablo Picasso can be 143 years outdated.
6. Iterating By way of a Vary of Dates
Generally it’s good to carry out an operation for on daily basis inside a selected date vary. You possibly can simply loop by means of dates by beginning with a date object and repeatedly including a timedelta of in the future till you attain the tip date.
import datetime
start_date = datetime.date(2025, 1, 1)
end_date = datetime.date(2025, 1, 7)
day_delta = datetime.timedelta(days=1)
current_date = start_date
whereas current_date
Output:
2025-01-01, Wednesday
2025-01-02, Thursday
2025-01-03, Friday
2025-01-04, Saturday
2025-01-05, Sunday
2025-01-06, Monday
2025-01-07, Tuesday
7. Parsing Dates from Non-Commonplace String Codecs
The strptime() operate is beneficial for changing strings to datetime objects. It’s extremely versatile and might deal with all kinds of codecs by utilizing particular format codes. That is important when coping with information from completely different sources that will not use a normal ISO format.
import datetime
date_string_1 = "July 4, 1776"
date_string_2 = "1867-07-01 14:30:00"
# Parse the primary string format
dt_object_1 = datetime.datetime.strptime(date_string_1, "%B %d, %Y")
print(f"Parsed object 1: {dt_object_1}")
# Parse the second string format
dt_object_2 = datetime.datetime.strptime(date_string_2, "%Y-%m-%d %H:%M:%S")
print(f"Parsed object 2: {dt_object_2}")
Output:
Parsed object 1: 1776-07-04 00:00:00
Parsed object 2: 1867-07-01 14:30:00
8. Discovering the Nth Weekday of a Month
Do you need to know the date of the third Thursday in November? The calendar module can be utilized alongside datetime to unravel this. The monthcalendar() operate returns a matrix representing the weeks of a month, which you’ll be able to then parse.
import calendar
# calendar.weekday() Monday is 0 and Sunday is 6
# calendar.Thursday is 3
cal = calendar.Calendar()
# Get a matrix of weeks for November 2025
month_matrix = cal.monthdatescalendar(2025, 11)
# Discover the third Thursday
third_thursday = [week[calendar.THURSDAY] for week in month_matrix if week[calendar.THURSDAY].month == 11][2]
print(f"The third Thursday of Nov 2025 is: {third_thursday}")
Output:
The third Thursday of Nov 2025 is: 2025-11-20
9. Getting the ISO Week Quantity
The ISO 8601 commonplace defines a system for week numbering the place per week begins on a Monday. The isocalendar() technique returns a tuple containing the ISO 12 months, week quantity, and weekday for a given date.
Word that the date beneath is a Thursday, and so ought to lead to a day of the week of 4. It must also be the twenty eighth week of the 12 months.
import datetime
d = datetime.date(2025, 7, 10)
iso_cal = d.isocalendar()
print(f"Date: {d}")
print(f"ISO Yr: {iso_cal[0]}")
print(f"ISO Week Quantity: {iso_cal[1]}")
print(f"ISO Weekday: {iso_cal[2]}")
Output:
Date: 2025-07-10
ISO Yr: 2025
ISO Week Quantity: 28
ISO Weekday: 4
10. Including or Subtracting Enterprise Days
Calculating future dates whereas skipping weekends is a typical enterprise requirement. Whereas datetime does not have a built-in operate for this, you possibly can write a easy helper operate utilizing timedelta and the weekday() technique.
import datetime
def add_business_days(start_date, num_days):
current_date = start_date
whereas num_days > 0:
current_date += datetime.timedelta(days=1)
# weekday() returns 5 for Saturday and 6 for Sunday
if current_date.weekday()
13 enterprise days after 2025-07-10 is 2025-07-29
Wrapping Up
Python’s datetime module is greater than only a easy software for storing dates. It offers a versatile and helpful set of instruments for dealing with nearly any time-related logic conceivable. By understanding its core elements — date, time, datetime, and timedelta — and mixing them with the calendar module or exterior libraries like pytz, you possibly can remedy complicated real-world issues effectively and precisely.
Remember to take a look at the datetime module’s documentation for extra. You is perhaps stunned at what you possibly can accomplish.
Matthew Mayo (@mattmayo13) holds a grasp’s diploma in laptop science and a graduate diploma in information mining. As managing editor of KDnuggets & Statology, and contributing editor at Machine Studying Mastery, Matthew goals to make complicated information science ideas accessible. His skilled pursuits embrace pure language processing, language fashions, machine studying algorithms, and exploring rising AI. He’s pushed by a mission to democratize data within the information science neighborhood. Matthew has been coding since he was 6 years outdated.
