Datetime module in Python programming language

The python programming language is widely used in various industries, including finance, healthcare, and technology, among others. One of the essential modules in python is the Datetime module, which provides developers with a powerful set of tools to manipulate date and time information. In this tutorial, we will explore the Datetime module in python and show you the various ways you can work with date and time data types. 

Datetime module in Python

• Python's   datetime   module provides a number of ways to manipulate dates and times. 
• The   datetime   module in Python is a module that is used to work with 
  • dates, 
  • times, and 
  • time intervals. 
• It provides various classes, methods, and functions to work with date and time.
• The   datetime   module exports four types: 
  • date : date objects represent a date (day, month, and year) in an idealized calendar, the current Gregorian calendar indefinitely extended in both directions. 
  • time : time objects represent a time (hour, minute, second, sub-second) on an idealized clock. 
  • datetime : datetime objects combine both date and time information into a single object. 
  • timedelta : timedelta objects represent the difference between two datetime objects. 

Datetime Class

• The   datetime  module contains the class with same name i.e.   datetime .
• The  datetime  class is the main class in the  datetime  module.
• It is used to represent dates and times.
• This name clash between the module and the class can be a little confusing. One need to be careful while using the import statement.
• We can access the  datetime  class in two ways.
• The first method is by using the dot operator :
  • We can import only the   datetime  module using the code :  import datetime 
  • Then we can access the  datetime  class using dot operator :  datetime.datetime 
  • Code sample :  The code sample below imports the  datetime  module and then accesses the  datetime  class using the dot operator.

# importing the module
import datetime

# Accessing datetime class
dt = datetime.datetime

print(dt.now())

• Second method of accessing the  datetime  class is by importing it in import statement.
  • To import The   datetime  class from the module we need to write :  from datetime import datetime 
  • Code Sample : 

# importing the class
from datetime import datetime

# Using datetime class
dt = datetime.now()

print(dt)

Getting Current Date and Time

• The  datetime  class has a method called  now()  which returns the current date and time.
• The  datetime  class also has methods to get the current year, month, day, hour, minute, second, and microsecond.

from datetime import datetime

# Get the current date and time
now = datetime.now()
print(now)
print()

# Print the current year, month, day, hour, minute, second, and microsecond
print(f"Current Year : {now.year}, \n"
      f"Current Month : {now.month}, \n"
      f"Current Day : {now.day}, \n"
      f"Current Hour : {now.hour}, \n"
      f"Current Minute : {now.minute},\n"
      f"Current Second : {now.second}, \n"
      f"Current microsecond : {now.microsecond}")
      

Creating a Datetime Object

• We can create a  datetime  object using the  datetime  class constructor.
• The constructor takes arguments for year, month, day, hour, minute, second, and microsecond.
• The  datetime  object is actually a date with year, month, day, hour, minute, second, and microsecond components.
• If we omit the hour, minute, second, and microsecond arguments they take the default value of zero.
• The year, month, day arguments are mandatory.
• Code Sample : 

import datetime

# Creating a datetime object
dt = datetime.datetime(2011, 4, 12, 10, 20, 0, 44)

# Printing the datetime object
print("datetime object = ", dt)
print()


# Print the year, month, day, hour, minute, second, and microsecond of the date
print(f"Year : {dt.year}, \n"
      f"Month : {dt.month}, \n"
      f"Day : {dt.day}, \n"
      f"Hour : {dt.hour}, \n"
      f"Minute : {dt.minute},\n"
      f"Second : {dt.second}, \n"
      f"microsecond : {dt.microsecond}")
      
    
        
# Output
# datetime object =  2009-04-12 10:20:00.000044

# Year : 2011, 
# Month : 4, 
# Day : 12, 
# Hour : 10, 
# Minute : 20,
# Second : 0, 
# microsecond : 44 
 
      
      

Formatting a Datetime Object :

• The  strftime()  method is used to format a  datetime  object.
• It takes a format string as an argument and returns the   datetime  object as a formatted string.
• The format string uses some format codes that indicates what should be the format of the output string.
• Our next tutorial deals with strftime() method in detail and contains a full list of format codes that we can use.
• Code Sample : 

import datetime

# Creating a datetime object
dt = datetime.datetime(2015, 10, 25, 10, 30, 0)

# Formatting the datetime object
formatted_date = dt.strftime("%A, %d %B %Y %I:%M:%S %p")

print(formatted_date)


# Output
# Sunday, 25 October 2015 10:30:00 AM

Converting a String to a Datetime Object :

• The  strptime()  method is used to convert a string to a  datetime  object.
• It takes the string and the format string as arguments and returns a  datetime  object.
• Our tutorial on strptime() method discusses this method in detail.
• Code Sample : 

from datetime import datetime

# Convert a string to a datetime object
dt_string = "2015-10-25 10:30:00"
dt_object = datetime.strptime(dt_string, "%Y-%m-%d %H:%M:%S")

# Print the datetime object
print(dt_object)

# Output
# 2015-10-25 10:30:00

Working with Time Intervals :

• The  timedelta  class of the   datetime  module is used to represent time duration.
• We can use   timedelta  to represent time duration in form of days, hours, minutes, seconds, and microseconds.
• We can import the  timedelta  class by using the construct :  from datetime import timedelta 
• The  timedelta  class can be used to perform arithmetic on dates and times. 
• In this section, we present a couple of methods of performing timedelta arithmetic.
• We have a detailed tutorial on timedelta class which discusses many other ways in which we can do arithmetic with timedelta objects.

Find difference between two dates

• We can find the difference between two dates using the subtraction operator to get a   timedelta  object.
• Code Sample :

from datetime import date

d1 = date(2017, 5, 19)
d2 = date(2017, 5, 15)

# Getting the difference between two dates
diff = d1 - d2
print("Time Diff :", diff)
print("Data type of diff : ", type(diff))
print()


# Output
# Time Diff : 4 days, 0:00:00
# Data type of diff :  <class 'datetime.timedelta'>

Add a time duration to datetime object

• We can add a time duration to a  datetime  object using   timedelta   to get a new  datetime  object.
• Code sample : 

from datetime import datetime
from datetime import timedelta

# Adding a time duration to a datetime object
dt = datetime(2017, 5, 9)
new_date = dt + timedelta(days=7)

print("Orig. date :", dt)
print("New date   :", new_date)
print("Data type of New date :", type(new_date))
print()


# Output
# Orig. date : 2017-05-09 00:00:00
# New date   : 2017-05-16 00:00:00
# Data type of New date : <class 'datetime.datetime'>

Working with Timezones

• The  pytz  module can be used to work with timezones.
• It provides classes to represent timezones and to convert between timezones.
• The code sample below shows how we can use the  pytz  module in python.
• Our tutorial on timezones discusses timezones in python in detail.
• Code Sample : 

import datetime
import pytz

utc_time = datetime.datetime(2017, 5, 9)
utc_zone = pytz.utc
local_zone = pytz.timezone('Asia/Kolkata')
local_time = utc_time.astimezone(local_zone)

print(local_time.strftime('%Y-%m-%d %H:%M:%S %Z%z'))


# Output
# 2017-05-09 00:00:00 IST+0530

Different Classes of datetime module in Python : 

• The datetime module consists of a number of functions and classes for manipulating dates and times. 
• Below are the classes contained in the datetime module :
  • datetime.date class. 
  • datetime.time class. 
  • datetime.datetime class. 
  • datetime.timedelta class. 
  • datetime.tzinfo class
  • datetime.timezone class

datetime.date class :

• The datetime.date class represents a date object. 
• The datetime.date class has the following methods: 
  • datetime.date.today() 
  • datetime.date.fromtimestamp() 
  • datetime.date.fromordinal() 
  • datetime.date.weekday() 
  • datetime.date.isoweekday() 
  • datetime.date.isocalendar() 
  • datetime.date.isoformat() 
  • datetime.date.strftime() 
  • datetime.date.__str__() 

datetime.time class :

• The datetime.time class represents a time object. 
• The datetime.time class has the following methods: 
  • datetime.time.hour 
  • datetime.time.minute 
  • datetime.time.second 
  • datetime.time.microsecond 
  • datetime.time.tzinfo 
  • datetime.time.isoformat() 
  • datetime.time.strftime() 
  • datetime.time.__str__() 

datetime.datetime class :

• The datetime.datetime class represents a datetime object. 
• The datetime.datetime class has the following methods: 
  • datetime.datetime.today() 
  • datetime.datetime.now() 
  • datetime.datetime.utcnow() 
  • datetime.datetime.fromtimestamp() 
  • datetime.datetime.utcfromtimestamp() 
  • datetime.datetime.fromordinal() 
  • datetime.datetime.combine() 
  • datetime.datetime.date() 
  • datetime.datetime.time() 
  • datetime.datetime.timetz() 
  • datetime.datetime.astimezone() 
  • datetime.datetime.replace() 
  • datetime.datetime.strptime() 
  • datetime.datetime.isoformat() 
  • datetime.datetime.strftime() 
  • datetime.datetime.__str__() 

datetime.timedelta class :

• The datetime.timedelta class represents the difference between two datetime objects. 
• The datetime.timedelta class has the following methods: 
  • datetime.timedelta.days 
  • datetime.timedelta.seconds 
  • datetime.timedelta.microseconds 
  • datetime.timedelta.total_seconds() 
  • datetime.timedelta.__str__() 

datetime.tzinfo class :

• The datetime.tzinfo class is an abstract base class for time zone information objects. 
• These objects provide methods for converting datetime objects from one time zone to another.
• It is an abstract base class for time zone objects.

datetime.timezone class

• datetime.timezone class implements the  tzinfo  abstract base class as a fixed offset from the UTC.