Python Compare Two Dates

In this lesson, you’ll learn how to compare two dates or datetime in Python.

You’ll learn how to:

• Check if a given date is greater or less than another date.
• Compare two timestamps
• Compare two date string

How to Compare Two Dates in Python

Example 1: Compare Two DateTime

In this example, we’ll check:

• If the datetime_1 is greater than another datetime.
• If the datetime_1 is lower than datetime_2.

from datetime import datetime

def compare_dates(date1, date2):
    print('Date1:', date1)
    print('Date2:', date2)

    if date1 > date2:
        print('Date1 is greater than date2')
    else:
        print('Date1 is lower than date2')

dt1 = datetime(2022, 9, 13)
# today's datetime
today = datetime.now()
compare_dates(dt1, today)

dt1 = datetime(2022, 9, 13)
dt2 = datetime(2021, 11, 23)
compare_dates(dt1, dt2)

Output:

Date1: 2022-09-13 00:00:00
Date2: 2022-10-07 15:12:52.970943
Date1 is lower than date2

Date1: 2022-09-13 00:00:00
Date2: 2021-11-23 00:00:00
Date1 is greater than date2

Example 2: Compare Two Dates

Let’s assume you have two datetime objects. One only has the date, and the other one has the date & time parts, and you want to compare the dates only (and not the time).

Now, If you want to compare only the dates of DateTime objects, just use the date() method to extract only the date part from the datetime object.

from datetime import datetime

# input dates
d1 = datetime(2022, 6, 27).date()
d2 = datetime(2022, 6, 27).date()
d3 = datetime(2021, 5, 14).date()
d4 = datetime(2022, 10, 10).date()

# omit .date() function if you want to compare the entire datetime object
# use .date() id you want to compare only the date part of it

# date equality check
print('Date_1:', d1, 'Date_2:', d2, 'Date3:', d3)
print('Date_1 and Date_2 are equal:', d1 == d2)
print('Date_1 and Date_3 are equal:', d1 == d3)

# check if date is greater than another date
print('Date_1:', d1, 'Date_3:', d3, 'Date_4:', d4)
print('date_1 is greater than date_3:', d1 > d3)
print('date_1 is greater than date_4:', d1 > d4)

# check if date is less than another date
print('Date_1:', d1, 'Date_3:', d3, 'Date_4:', d4)
print('date_1 is less than date_3:', d1 < d3)
print('date_1 is less than date_4:', d1 < d4)

# date not equal to check
print('Date_1:', d1, 'Date_2:', d2, 'Date__3:', d3)
print('Date_1 and Date_2 are NOT equal:', d1 != d2)
print('Date_1 and Date_3 are NOT equal:', d1 != d3)

Output:

Date_1: 2022-06-27 Date_2: 2022-06-27 Date3: 2021-05-14
Date_1 and Date_2 are equal: True
Date_1 and Date_3 are equal: False

Date_1: 2022-06-27 Date_3: 2021-05-14 Date_4: 2022-10-10
date_1 is greater than date_3: True
date_1 is greater than date_4: False

Date_1: 2022-06-27 Date_3: 2021-05-14 Date_4: 2022-10-10
date_1 is less than date_3: False
date_1 is less than date_4: True

Date_1: 2022-06-27 Date_2: 2022-06-27 Date__3: 2021-05-14
Date_1 and Date_2 are NOT equal: False
Date_1 and Date_3 are NOT equal: True

Example 3: Compare Times of two DateTime Objects

Let’s assume you have two datetime objects. One only has the time, and the other one has the date & time parts, and you want to compare the times only (and not the date).

Use the time() method to extract only the time part from the datetime object.

Example:

from datetime import datetime

# date in yyyy/-mm-dd hh:mm:ss format
dt_1 = datetime(2022, 6, 27, 18, 45, 53)
dt_2 = datetime(2022, 6, 27, 21, 12, 34)

# use .time() if you want to compare only the time part of it

# date equality check
print('Time_1:', dt_1.time(), 'Time_2:', dt_2.time())

print('Both times are equal:', dt_1.time() == dt_2.time())
print('Times not equal:', dt_1.time() != dt_2.time())

print('Time_1 is greater than Time_2:', dt_1.time() > dt_2.time())
print('Time_1 is less than Time_2:', dt_1.time() < dt_2.time())

Output:

Time_1: 18:45:53 Time_2: 21:12:34

Both times are equal: False
Times not equal: True

Time_1 is greater than Time_2: False
Time_1 is less than Time_2: True

Compare Two Date String

There may be a case in which dates are in a string format. Before comparing them, we need to convert both date strings to a datetime object.

Use the strptime(date_str, format) function to convert a date string into a datetime object as per the corresponding format. The format codes are standard directives for mentioning the string format for parsing. For example, the %Y/%m/%d format codes are for yyyy-mm-dd.

Example:

from datetime import datetime

def compare_dates(date1, date2):
    # convert string to date
    dt_obj1 = datetime.strptime(date1, "%Y-%m-%d %H:%M:%S")
    dt_obj2 = datetime.strptime(date2, "%Y-%m-%d %H:%M:%S")
    print('Date1:', dt_obj1)
    print('Date2:', dt_obj2)

    if dt_obj1 == dt_obj2:
        print('Both dates are equal')
    elif dt_obj1 > dt_obj2:
        print('Date1 is greater than date2')
    else:
        print('Date1 is lower than date2')

# datetime in yyyy-mm-dd hh:mm:ss format
dt_str1 = '2022-10-29 8:32:49'
dt_str2 = '2022-5-7 4:14:58'
compare_dates(dt1_str1, dt2_str2)

Output:

Date1: 2022-10-29 08:32:49
Date2: 2022-05-07 04:14:58
Date1 is greater than date2

Compare Two Timestamps in Python

A timestamp is encoded information generally used in UNIX, which indicates the date and time at which a particular event has occurred. This information could be accurate to the microseconds. It is a POSIX timestamp corresponding to the datetime instance.

To compare Python timestamp objects, we can use the same conditional operator we used to compare dates.

Example:

from datetime import datetime

# input timestamp
ts1 = datetime(2022, 6, 27, 18, 45, 32).timestamp()
# get current timestamp
ts2 = datetime.now().timestamp()

print('Timestamp_1:', ts1, 'Timestamp_2:', ts2)
# timestamp equality check
print('Timestamp_1 and Timestamp_2 are equal:', ts1 == ts2)

# check if timestamp_1 is greater than another timestamp
print('Timestamp_2 is greater than Timestamp_1:', ts2 > ts1)

# check if timestamp_1 is less than another timestamp
print('Timestamp_1 is less than Timestamp_2:', ts1 < ts2)

# timestamp not equal to check
print('Timestamp_1 is NOT equal to Timestamp_2:', ts1 != ts2)

Output:

Timestamp_1: 1656335732.0 Timestamp_2: 1665393979.484924

Timestamp_1 and Timestamp_2 are equal: False
Timestamp_2 is greater than Timestamp_1: True
Timestamp_1 is less than Timestamp_2: True
Timestamp_1 is NOT equal to Timestamp_2: True