How to add and subtract days using DateTime in Python?

As we know date and time are used in programs where we have to keep track of date and time, so it is necessary to have a module to manipulate date and time. In python, a Date Time module deals with dates and times. Date time module is built into Python standard library.

Datetime module consists of the following classes:

	Name	Description
1.	date	It shows the date according to the Georgian calendar with attributes are year, month and day.
2.	time	It shows time, independent of any particular day with attributes are hour, minute, second, microsecond, and tzinfo.
3.	datetime	It is a collection of date and time with the attributes year, month, day, hour, minute, second, microsecond, and tzinfo.
4.	timedelta	It is used to manipulate date.
5.	tzinfo	It provides information about time zone.

Add and subtract days using DateTime in Python

For adding or subtracting date, we use something called timedelta() function which can be found under datetime class.  It is used to manipulate date, and we can perform an arithmetic operations on date like adding or subtract. timedelta is very easy and useful to implement.

Syntax: class datetime.timedelta(days=10, seconds=40, microseconds=10, milliseconds=60, minutes=10, hours=4, weeks=8)

Returns : Date

Note : if we doesn’t specify by default it takes integer as an day. 

Example 1. Adding Days 

Python3

# MANIPULATING DATETIME
from datetime import date, timedelta

today_date = date.today()

print("CURRENT DAY : ", today_date)

# as said earlier it takes argument as day by default
td = timedelta(5)
print("AFTER 5 DAYS DATE WILL BE : ", today_date + td)

Output: 

CURRENT DAY :  2020-12-27
AFTER 5 DAYS DATE WILL BE :  2021-01-01

Example 2. Subtract Days 

Python3

# MANIPULATING DATETIME
from datetime import date, timedelta

current_date = date.today()

print("CURRENT DAY : ",current_date)

print("OLD Date : ",current_date - timedelta(17))

Output:

CURRENT DAY :  2020-12-27
OLD Date :  2020-12-10

As in the above code, I have created a variable called current_date which holds the current date, and then prints that current date.

After that, I have used timedelta function and in the parameter, We have passed a value that how many days want to add or subtract (This value can be any integer).

Similarly, we can do the same with time also.   

Example 3:

Python3

# Manipulate DATETIME
from datetime import datetime, timedelta
current = datetime.now()
print("This is the current date and time :- ", current)

# FOR PRINTING TOMORROW'S DATE
tomorrow = timedelta(1)
print("Tomorrow's date and time :- ", current + tomorrow)

# FOR PRINTING YESTERDAY'S DATE
yesterday = timedelta(-1)
print("Yesterday's date and time :- ", current + yesterday)

Output:

This is the current date and time :-  2020-12-27 13:50:14.229336
Tomorrow's date and time :-  2020-12-28 13:50:14.229336
Yesterday's date and time :-  2020-12-26 13:50:14.229336

Example 4:

Python3

# MANIPULATING DATETIME
from datetime import datetime, timedelta

curr = datetime.now()
print("Current Date and time :- ", curr)

new_datetime = timedelta(days = 10, seconds = 40,
                         microseconds = 10,
                         milliseconds = 60,
                         minutes = 10, hours = 4,
                         weeks = 8)

print("New Date and time :- ", curr + new_datetime)

Output: 

Current Date and time :-  2020-12-27 13:58:42.178211
New Date and time :-  2021-03-03 18:09:22.238221