Python Date Time Operations Tutorial with Examples

Python datetime library provides a lot of different functionalities to operate with date and time values. Python datetime library can be found later versions from 2.3. There are datetime library-related libraries like time and calendar if you are interested in a specific issue.

What is Time?

Time values are represented with time class. Time class gives the ability to hold values like an hour, minute, second, microsecond. Time values also hold time zone information.

Create Time Object With Current Time

We will create a new time object with the current time. Time objects will hold values like hour, minute, second, time zone values.

from datetime import datetime, date, time 
 
t = datetime.now() 
print t 
print 'hour  :', t.hour 
print 'minute:', t.minute 
print 'second:', t.second 
print 'microsecond:', t.microsecond 
print 'tzinfo:', t.tzinfo

Time Object Minimum and Maximum Values

Time object has limits to express values. Below maximum and minimum values are printed by using min and max properties.

import datetime 
 
print 'Min    :', datetime.time.min 
print 'Max    :', datetime.time.max 
print 'Resolution:', datetime.time.resolution

Create Time Object Providing Values

A new time object can be created by providing minute, second and other related values with parameters.

import datetime 
 
t = datetime.time(3, 2, 1) 
print t 
print 'hour  :', t.hour 
print 'minute:', t.minute 
print 'second:', t.second 
print 'microsecond:', t.microsecond 
print 'tzinfo:', t.tzinfo

Date Operations

Date class provides to hold information about the year, month, day. today function can be used to initialize new date object like below.

import datetime 
 
today = datetime.date.today() 
 
print today 
 
print 'tuple  :', today.timetuple() 
print 'ordinal:', today.toordinal() 
print 'Year   :', today.year 
print 'Month  :', today.month 
print 'Day    :', today.day

In this example, we print date-time information as a tuple with timetuple function.

Date Object Minimum and Maximum Values

Here are date object minimum and maximum values.

import datetime 
 
print 'Minimum    :', datetime.date.min 
print 'Maximum    :', datetime.date.max 
print 'Resolution :', datetime.date.resolution

Copy Date Instance With New Values

Existing date instance or object can be copied to the new date object by using the replace() function. Replace function will replace if a property and value are given below.

import datetime 
 
d1 = datetime.date(2015, 1, 1) 
print 'date1:', d1 
 
d2 = d1.replace(year=2016) 
print 'date2:', d2

Time Delta Or Time Difference

Time delta can be used to get the difference between two date and time objects. We define two date object 1.1.2015 and 1.1.2016. Then we get time delta of two date objects and print it.

import datetime 
 
d1 = datetime.date(2015, 1, 1) 
print 'date1:', d1 
 
d2 = d1.replace(2016, 1, 1) 
print 'date2:', d2 
 
 
td=d2-d1 
print 'Difference:'+str(td)

Date Arithmetic

Arithmetic operators can be used to operate on date and time objects. We can sum these time objects like below.

import datetime 
 
today = datetime.date.today() 
print 'Today    :', today 
 
two_day = datetime.timedelta(days=2) 
print 'Two day  :', two_day 
 
before_yesterday = today - two_day 
print 'Before Yesterday:', before_yesterday 
 
after_tomorrow = today + two_day 
print 'After Tomorrow :', after_tomorrow 
 
print 'tomorrow - yesterday:', after_tomorrow - before_yesterday 
print 'yesterday - tomorrow:', before_yesterday - after_tomorrow

Comparing Date and Time

Comparing date and time objects are similar to primitive data types like integer and string. We can compare two objects with regular compare keywords and operators.

import datetime 
import time 
 
print 'Times:' 
t1 = datetime.time(11, 55, 0) 
print '\tt1:', t1 
t2 = datetime.time(12, 5, 0) 
print '\tt2:', t2 
print '\tt1 < t2:', t1 < t2 
 
print 'Dates:' 
d1 = datetime.date.today() 
print '\td1:', d1 
d2 = datetime.date.today() - datetime.timedelta(days=1) 
print '\td2:', d2 
print '\td1 > d2:', d1 > d2

Date and Time Formatting

While printing to the stdout or other direction date and time formats can be formatted with strftime() function like below.

import datetime 
 
format = "%b %a %d %H:%M:%S %Y" 
 
today = datetime.datetime.today() 
print 'ISO     :', today 
 
s = today.strftime(format) 
print 'strftime:', s 
 
d = datetime.datetime.strptime(s, format) 
print 'strptime:', d.strftime(format)