In this tutorial, we will introduce how to compare python date or datetime for python beginners.

1.Preliminary

We can not compare date and datetime object in python, otherwise, we will get an error:

For example:

datetime.datetime.now() >= datetime.date.today()

Run this code, you will get an error:

TypeError: can't compare datetime.datetime to datetime.date

2.Compare date

Look at this example:

from datetime import datetime, date

date1 = date(1995, 3, 20)
date2 = date(2020, 1, 1)

Here date1 and date2 are date objects.

print("date1 comes before date2?", date1 < date2)
print("date1 comes after date2?", date1 > date2)
print("date1 is equal to date2?", date1 == date2)

Run this code, you will get the compared result.

date1 comes before date2? True
date1 comes after date2? False
date1 is equal to date2? False

3.Compare datetime

dob_a = datetime(1995, 3, 20)
dob_b = datetime(2020, 1, 1)

Here dob_a and dob_b are datetime objects.

We can compare them as follows:

if  dob_a > dob_b:
    print("person a is older than person b")
else:
    print("person b is older than person a")

Run this code, you will see:

person b is older than person a

4.Compare date and datetime with timezone

We should localize the given date according to the timezone objects. Here is an example:

from datetime import datetime
import pytz

# Create timezone objects for different parts of the world
tz_ny= pytz.timezone('America/New_York')
tz_lon = pytz.timezone("Europe/London")

# Year, Month, Day, Hour, Minute, Second
datetime = datetime(2010, 4, 20, 23, 30, 0)

# Localize the given date, according to the timezone objects
date_with_timezone_1 = tz_ny.localize(datetime)
date_with_timezone_2 = tz_lon.localize(datetime)

In this example code, we use pytz.timezone() to create two timezones and use .localize() function to localize a given datetime. Then, we can compare them.

# These are now, effectively no longer the same *date* after being localized
print(date_with_timezone_1) # 2010-04-20 23:30:00-04:00
print(date_with_timezone_2) # 2010-04-20 23:30:00+01:00

print(date_with_timezone_1 == date_with_timezone_2)