How to compare two dates?

python

datetime

date-comparison

time-keeping

byAnton Shumikhin·Jan 25, 2025

With Python, comparing two dates is as simple as datetime objects and playing with comparison operators:

from datetime import datetime

# "Birth" of our datetime objects from strings
date1 = datetime.strptime('2023-03-14', '%Y-%m-%d')
date2 = datetime.strptime('2023-03-18', '%Y-%m-%d')

# Fast and furious comparison
print("date1 is earlier than date2") if date1 < date2 else print("date1 is the same or later than date2")

This statement checks if the date1 came into the world before date2 using the < operator. We're also printing the result using Python's slick one-liner if statement.

For creating a suspenseful time-difference movie or performing date arithmetic, we'll need to introduce you to timedelta. Want an example? Let's go:

from datetime import timedelta

# Assuming date1 and date2 are still our prime protagonists
time_difference = date2 - date1
if time_difference > timedelta(days=30):
    print("Dates are more than a month apart, long-time no see!")

This piece of wisdom encapsulates the importance of datetime arithmetic. Not only does it compare dates, it also "tells" the days between dates.

Practicality of date comparison

Enough said about theory, let's dive deeper into the real-world implications that date comparisons have on task automation and workflow management. Ready?

Running the event show

Event enthusiasts can employ date comparisons to determine if the event date is past-due and automate follow-up emails or surveys:

# Assuming event_date and current_datetime are defined as above
if current_datetime > event_date:
    trigger_email_feedback_request() # "Nice party! How about some feedback?"

Admin's best friend

SysAdmins might use date comparisons to analyze if last login dates tastes stale and depending on this trigger password resets or account review:

# Assuming last_login and stale_date are defined as above
if last_login < stale_date:
    trigger_password_reset() # "Long time no see, let's refresh memory!"

Data freshness guaranteed

In the world of data processing, comparing dates is an authenticity check, ensuring that the data is still relevant and updates records sufficiently:

# Assuming record_date and data_expiry_date are defined as above
if record_date < data_expiry_date:
    update_data_record() # Keeping it fresh like a lemon squeeze!

Alerts & notifications

Notification systems such as subscription expiring alerts, date comparison can be utilized to trigger alert emails:

# Assuming today and subscription_end_date are defined as above
if today > subscription_end_date - timedelta(days=7):
    send_renewal_alert() # "Time to renew, don't let it get overdue!"

Each such context, and more, cherishes the fact that datetime objects can be compared using boolean logic to streamline workflows and orchestrate automation.

Visualization

Compiling two dates in Python is akin to calculating the distance between two points on a timeline:

Timeline:    [📅]------------------[📆]

📅 = Date 1 and 📆 = Date 2

We use the datetime module to measure the span between them:

from datetime import datetime
date1 = datetime(2023, 3, 25)
date2 = datetime(2023, 4, 10)
gap = date2 - date1

The distance looks something like this:

📅---[16 days]--->📆

Here, every dash '---' is a day. It's like playing a game of time hopscotch!

Sometimes, you don't need fancy dates, just plain old times. Here's how you can compare them using only the time method from the datetime module:

from datetime import datetime

# When we just want to "time" the comparison
time1 = datetime.strptime('08:30:00', '%H:%M:%S').time()
time2 = datetime.strptime('17:45:00', '%H:%M:%S').time()

print("time1 is earlier than time2") if time1 < time2 else print("time1 is the same or later than time2")