Comparing dates in Python

In Python, comparing dates is straightforward with the help of the datetime module. You can use basic comparison operators like <, >, ==, and != to compare two date or datetime objects directly. Below are a few common and practical ways to compare and sort dates in Python.

Basic Date Comparison

You can directly compare two datetime objects using standard comparison operators.

from datetime import datetime

d1 = datetime(2018, 5, 3)
d2 = datetime(2018, 6, 1)

print("d1 > d2:", d1 > d2)
print("d1 < d2:", d1 < d2)
print("d1 != d2:", d1 != d2)

d1 > d2: False
d1 < d2: True
d1 != d2: True

Explanation:

• datetime() creates a date-time object.
• operators like >, <, and != work directly on datetime objects.

Sorting a List of Dates

Dates can be stored in a list and sorted using the sort() method.

from datetime import date, timedelta

dates = [
    date.today(),
    date(2015, 6, 29),
    date(2011, 4, 7),
    date(2011, 4, 7) + timedelta(days=25)
]

dates.sort()

for d in dates:
    print(d)

2011-04-07
2011-05-02
2015-06-29
2025-04-22

Explanation:

• date.today() returns the current date.
• timedelta(days=25) adds days to a date.
• sort() arranges the list of dates in ascending order.

Using timedelta for Comparison

We can also use subtraction between date objects and compare the result using timedelta.

from datetime import date, timedelta

d1 = date(2022, 4, 1)
d2 = date(2023, 4, 1)

print("d1 > d2:", d1 - d2 > timedelta(0))
print("d1 < d2:", d1 - d2 < timedelta(0))
print("d1 != d2:", d1 != d2)

d1 > d2: False
d1 < d2: True
d1 != d2: True

Explanation:

• Subtracting two dates returns a timedelta object.
• Comparing with timedelta(0) shows which date is earlier/later.
• != checks if the dates are different.

Also read: sort(), timedelta, datetime object.