py

`datetime` module

datetime module
DateTime Module
Timedelta class
- Operations supported by Timedelta Class
Format Datetime
- Python Datetime strftime
- Python DateTime strptime
Handling Python DateTime timezone

A date in Python is not a data type of its own, but we can import a module named datetime to work with dates as date objects.

Import the datetime module and display the current date:

import datetime

x = datetime.datetime.now()
print(x)

When we execute the code from the example above the result will be:

2022-09-01 02:51:39.050514

The date contains year, month, day, hour, minute, second, and microsecond.

The datetime module has many methods to return information about the date object.

Date Output

Return the year and name of weekday:

import datetime

x = datetime.datetime.now()

print(x.year)
print(x.strftime("%A"))

Creating Date Objects

To create a date, we can use the datetime() class (constructor) of the datetime module.

The datetime() class requires three parameters to create a date: year, month, day.

Create a date object:

import datetime

x = datetime.datetime(2020, 5, 17)

print(x)

The datetime() class also takes parameters for time and timezone (hour, minute, second, microsecond, tzone), but they are optional, and has a default value of 0, (None for timezone).

The `strftime()` Method

The datetime object has a method for formatting date objects into readable strings.

The method is called strftime(), and takes one parameter, format, to specify the format of the returned string:

Display the name of the month:

import datetime

x = datetime.datetime(2018, 6, 1)

print(x.strftime("%B"))

A reference of all the legal format codes:

Directive	Description	Example
`%a`	Weekday, short version	Wed
`%A`	Weekday, full version	Wednesday
`%w`	Weekday as a number 0-6, 0 is Sunday	3
`%d`	Day of month 01-31	31
`%b`	Month name, short version	Dec
`%B`	Month name, full version	December
`%m`	Month as a number 01-12	12
`%y`	Year, short version, without century	18
`%Y`	Year, full version	2018
`%H`	Hour 00-23	17
`%I`	Hour 00-12	05
`%p`	AM/PM	PM
`%M`	Minute 00-59	41
`%S`	Second 00-59	08
`%f`	Microsecond 000000-999999	548513
`%z`	UTC offset	+0100
`%Z`	Timezone	CST
`%j`	Day number of year 001-366	365
`%U`	Week number of year, Sunday as the first day of week, 00-53	52
`%W`	Week number of year, Monday as the first day of week, 00-53	52
`%c`	Local version of date and time	Mon Dec 31 17:41:00 2018
`%C`	Century	20
`%x`	Local version of date	12/31/18
`%X`	Local version of time	17:41:00
`%%`	A % character	%
`%G`	ISO 8601 year	2018
`%u`	ISO 8601 weekday (1-7)	1
`%V`	ISO 8601 weeknumber (01-53)	01

DateTime Module

In Python, date and time are not a data type of their own, but a module named datetime can be imported to work with the date as well as time. Python Datetime module comes built into Python, so there is no need to install it externally.

Python Datetime module supplies classes to work with date and time. These classes provide a number of functions to deal with dates, times and time intervals. Date and datetime are an object in Python, so when you manipulate them, you are actually manipulating objects and not string or timestamps.

The DateTime module is categorized into 6 main classes –

date – An idealized naive date, assuming the current Gregorian calendar always was, and always will be, in effect. Its attributes are year, month and day.
time – An idealized time, independent of any particular day, assuming that every day has exactly 246060 seconds. Its attributes are hour, minute, second, microsecond, and tzinfo.
datetime – Its a combination of date and time along with the attributes year, month, day, hour, minute, second, microsecond, and tzinfo. timedelta – A duration expressing the difference between two date, time, or datetime instances to microsecond resolution.
tzinfo – It provides time zone information objects.
timezone – A class that implements the tzinfo abstract base class as a fixed offset from the UTC (New in version 3.2).

Date class

The date class is used to instantiate date objects in Python. When an object of this class is instantiated, it represents a date in the format YYYY-MM-DD. Constructor of this class needs three mandatory arguments year, month and date.

Constructor syntax:

class datetime.date(year, month, day)

The arguments must be in the following range –

MINYEAR <= year <= MAXYEAR
1 <= month <= 12
1 <= day <= number of days in the given month and year

Note – If the argument is not an integer it will raise a TypeError and if it is outside the range a ValueError will be raised.

Example 1: Date object representing date in Python

# Python program to demonstrate date class

# import the date class
from datetime import date
 
# initializing constructor
# and passing arguments in the
# format year, month, date
my_date = date(1996, 12, 11)
 
print("Date passed as argument is", my_date)
 
# Uncommenting my_date = date(1996, 12, 39)
# will raise an ValueError as it is
# outside range
 
# uncommenting my_date = date('1996', 12, 11)
# will raise a TypeError as a string is
# passed instead of integer

Output:

```Date passed as argument is 1996-12-11 Traceback (most recent call last): File “/home/ccabfb570d9bd1dcd11dc4fe55fd6ba2.py”, line 14, in my_date = date(1996, 12, 39) ValueError: day is out of range for month

Traceback (most recent call last): File “/home/53b974e10651f1853eee3c004b48c481.py”, line 18, in my_date = date(‘1996’, 12, 11) TypeError: an integer is required (got type str)

**Example 2: Get Current Date**
To return the current local date today() function of date class is used. today() function comes with several attributes (year, month and day). These can be printed individually. 


```py
# Python program to
# print current date
 
from datetime import date
 
# calling the today
# function of date class
today = date.today()
 
print("Today's date is", today)

Output

Today's date is 2021-08-19

Example 3: Get Today’s Year, Month, and Date

We can get the year, month, and date attributes from the date object using the year, month and date attribute of the date class.

from datetime import date
 
# date object of today's date
today = date.today()
 
print("Current year:", today.year)
print("Current month:", today.month)
print("Current day:", today.day)

Output ```Current year: 2021 Current month: 8 Current day: 19

**Example 4: Get date from Timestamp**

We can create date objects from timestamps y=using the fromtimestamp() method. The timestamp is the number of seconds from 1st January 1970 at UTC to a particular date.

```py
from datetime import datetime
 
# Getting Datetime from timestamp
date_time = datetime.fromtimestamp(1887639468)
print("Datetime from timestamp:", date_time)

Output

Datetime from timestamp: 2029-10-25 16:17:48

Example 5: Convert Date to String We can convert date object to a string representation using two functions isoformat() and strftime().

from datetime import date
   
# calling the today
# function of date class
today = date.today()
   
# Converting the date to the string
Str = date.isoformat(today)
print("String Representation", Str)
print(type(Str))

Output String Representation 2021-08-19 <class ‘str’>

List of Date class Methods

Function Name | Description –|– ctime() |Return a string representing the date fromisocalendar() |Returns a date corresponding to the ISO calendar fromisoformat() |Returns a date object from the string representation of the date fromordinal() |Returns a date object from the proleptic Gregorian ordinal, where January 1 of year 1 has ordinal 1 fromtimestamp() |Returns a date object from the POSIX timestamp isocalendar() |Returns a tuple year, week, and weekday isoformat() |Returns the string representation of the date isoweekday() |Returns the day of the week as integer where Monday is 1 and Sunday is 7 replace() |Changes the value of the date object with the given parameter strftime() |Returns a string representation of the date with the given format timetuple() |Returns an object of type time.struct_time today() |Returns the current local date toordinal() |Return the proleptic Gregorian ordinal of the date, where January 1 of year 1 has ordinal 1 weekday() |Returns the day of the week as integer where Monday is 0 and Sunday is 6

Time class

The time class creates the time object which represents local time, independent of any day.

**Constructor Syntax: **

class datetime.time(hour=0, minute=0, second=0, microsecond=0, tzinfo=None, *, fold=0)

All the arguments are optional. tzinfo can be None otherwise all the attributes must be integer in the following range –

<= hour < 24
<= minute < 60
<= second < 60
<= microsecond < 1000000
fold in [0, 1]

Example 1: Time object representing time in Python

# Python program to
# demonstrate time class
 
from datetime import time
 
# calling the constructor
my_time = time(13, 24, 56)
 
print("Entered time", my_time)
 
# calling constructor with 1
# argument
my_time = time(minute=12)
print("\nTime with one argument", my_time)
 
# Calling constructor with
# 0 argument
my_time = time()
print("\nTime without argument", my_time)
 
# Uncommenting time(hour = 26)
# will rase an ValueError as
# it is out of range
 
# uncommenting time(hour ='23')
# will raise TypeError as
# string is passed instead of int

Output:

Entered time 13:24:56

Time with one argument 00:12:00

Time without argument 00:00:00
Traceback (most recent call last):
  File "/home/95ff83138a1b3e67731e57ec6dddef25.py", line 21, in 
    print(time(hour=26))
ValueError: hour must be in 0..23

Traceback (most recent call last):
  File "/home/fcee9ba5615b0b74fc3ba39ec9a789fd.py", line 21, in 
    print(time(hour='23'))
TypeError: an integer is required (got type str)

Example 2: Get hours, minutes, seconds, and microseconds

After creating a time object, its attributes can also be printed separately.

from datetime import time
 
Time = time(11, 34, 56)
 
print("hour =", Time.hour)
print("minute =", Time.minute)
print("second =", Time.second)
print("microsecond =", Time.microsecond)

Output:

hour = 11
minute = 34
second = 56
microsecond = 0

Example 3: Convert Time object to String

We can convert time object to string using the isoformat() method.

from datetime import time
 
# Creating Time object
Time = time(12,24,36,1212)
 
# Converting Time object to string
Str = Time.isoformat()
print("String Representation:", Str)
print(type(Str))

Output

String Representation: 12:24:36.001212
<class 'str'>

List of Time class Methods

Function Name |Description –|– dst() |Returns tzinfo.dst() is tzinfo is not None fromisoformat() |Returns a time object from the string representation of the time isoformat() |Returns the string representation of time from the time object replace() |Changes the value of the time object with the given parameter strftime() |Returns a string representation of the time with the given format tzname() |Returns tzinfo.tzname() is tzinfo is not None utcoffset() |Returns tzinfo.utcffsets() is tzinfo is not None

Datetime class

The DateTime class contains information on both date and time. Like a date object, datetime assumes the current Gregorian calendar extended in both directions; like a time object, datetime assumes there are exactly 3600*24 seconds in every day.

Constructor Syntax:

class datetime.datetime(year, month, day, hour=0, minute=0, second=0, microsecond=0, tzinfo=None, *, fold=0) 

The year, month and day arguments are mandatory. tzinfo can be None, rest all the attributes must be an integer in the following range –

MINYEAR <= year <= MAXYEAR
<= month <= 12
<= day <= number of days in the given month and year
<= hour < 24
<= minute < 60
<= second < 60
<= microsecond < 1000000
fold in [0, 1]

Note – Passing an argument other than integer will raise a TypeError and passing arguments outside the range will raise ValueError.

**Example 1: DateTime object representing DateTime in Python **

# Python program to
# demonstrate datetime object
 
from datetime import datetime
 
# Initializing constructor
a = datetime(1999, 12, 12)
print(a)
 
# Initializing constructor
# with time parameters as well
a = datetime(1999, 12, 12, 12, 12, 12, 342380)
print(a)

Output:

1999-12-12 00:00:00
1999-12-12 12:12:12.342380

Example 2: Get year, month, hour, minute, and timestamp After creating a DateTime object, its attributes can also be printed separately.

from datetime import datetime
 
a = datetime(1999, 12, 12, 12, 12, 12)
 
print("year =", a.year)
print("month =", a.month)
print("hour =", a.hour)
print("minute =", a.minute)
print("timestamp =", a.timestamp())

Output:

year = 1999
month = 12
hour = 12
minute = 12
timestamp = 945000732.0

Example 3: Current date and time You can print the current date and time using the Datetime.now() function. now() function returns the current local date and time.

from datetime import datetime
 
# Calling now() function
today = datetime.now()
 
print("Current date and time is", today)

Output:

Current date and time is 2019-10-25 11:12:11.289834

Example 4: Convert Python Datetime to String

We can convert Datetime to string in Python using the datetime.strftime and datetime.isoformat methods.

from datetime import datetime as dt
 
# Getting current date and time
now = dt.now()
 
string = dt.isoformat(now)
print(string)
print(type(string))

Output

2021-08-19T18:13:25.346259
<class 'str'>

List of Datetime Class Methods

Function Name |Description –|– astimezone() |Returns the DateTime object containing timezone information. combine() |Combines the date and time objects and return a DateTime object ctime() |Returns a string representation of date and time date() |Return the Date class object fromisoformat() |Returns a datetime object from the string representation of the date and time fromordinal() |Returns a date object from the proleptic Gregorian ordinal, where January 1 of year 1 has ordinal 1. The hour, minute, second, and microsecond are 0 fromtimestamp() |Return date and time from POSIX timestamp isocalendar() |Returns a tuple year, week, and weekday isoformat() |Return the string representation of date and time isoweekday() |Returns the day of the week as integer where Monday is 1 and Sunday is 7 now() |Returns current local date and time with tz parameter replace() |Changes the specific attributes of the DateTime object strftime() |Returns a string representation of the DateTime object with the given format strptime() |Returns a DateTime object corresponding to the date string time() |Return the Time class object timetuple() |Returns an object of type time.struct_time timetz() |Return the Time class object today() |Return local DateTime with tzinfo as None toordinal() |Return the proleptic Gregorian ordinal of the date, where January 1 of year 1 has ordinal 1 tzname() |Returns the name of the timezone utcfromtimestamp() |Return UTC from POSIX timestamp utcoffset() |Returns the UTC offset utcnow() |Return current UTC date and time weekday() |Returns the day of the week as integer where Monday is 0 and Sunday is 6

Timedelta class

Python timedelta class is used for calculating differences in dates and also can be used for date manipulations in Python. It is one of the easiest ways to perform date manipulations.

Constructor syntax:

class datetime.timedelta(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=0, hours=0, weeks=0)

Returns : Date 

Example 1: Add days to datetime object

# Timedelta function demonstration
 
from datetime import datetime, timedelta
 
 
# Using current time
ini_time_for_now = datetime.now()
 
# printing initial_date
print("initial_date", str(ini_time_for_now))
 
# Calculating future dates
# for two years
future_date_after_2yrs = ini_time_for_now + timedelta(days=730)
 
future_date_after_2days = ini_time_for_now + timedelta(days=2)
 
# printing calculated future_dates
print('future_date_after_2yrs:', str(future_date_after_2yrs))
print('future_date_after_2days:', str(future_date_after_2days))

Output:

initial_date 2019-10-25 12:01:01.227848
future_date_after_2yrs: 2021-10-24 12:01:01.227848
future_date_after_2days: 2019-10-27 12:01:01.227848

Example 2: Difference between two date and times

Date and Time difference can also be found using this class.

# Timedelta function demonstration
from datetime import datetime, timedelta
 
# Using current time
ini_time_for_now = datetime.now()
 
# printing initial_date
print("initial_date", str(ini_time_for_now))
 
# Some another datetime
new_final_time = ini_time_for_now + \
    timedelta(days=2)
 
# printing new final_date
print("new_final_time", str(new_final_time))
 
 
# printing calculated past_dates
print('Time difference:', str(new_final_time -
                              ini_time_for_now))

Output:

initial_date 2019-10-25 12:02:32.799814
new_final_time 2019-10-27 12:02:32.799814
Time difference: 2 days, 0:00:00

Operations supported by Timedelta Class

Operator |Description –|– Addition (+) |Adds and returns two timedelta objects Subtraction (-) |Subtracts and returns two timedelta objects Multiplication () |Multiplies timedelta object with float or int Division (/) |Divides the timedelta object with float or int Floor division (//) |Divides the timedelta object with float or int and return the int of floor value of the output Modulo (%) |Divides two timedelta object and returns the remainder +(timedelta) |Returns the same timedelta object -(timedelta) |Returns the resultant of -1timedelta abs(timedelta) |Returns the +(timedelta) if timedelta.days > 1=0 else returns -(timedelta) str(timedelta) |Returns a string in the form (+/-) day[s], HH:MM:SS.UUUUUU repr(timedelta) |Returns the string representation in the form of the constructor call

Format Datetime

Formatting Datetime can be very necessary as the date representation may differe from place to place. Like in some countries it can be yyyy-mm-dd and in other country it can be dd-mm-yyyy. To format Python Datetime strptime and strftime functions can be used.

Python Datetime strftime

strftime() method converts the given date, time or datetime object to the a string representation of the given format.

Example: Python Datetime format

# Python program to demonstrate
# strftime() function
 
 
from datetime import datetime as dt
 
# Getting current date and time
now = dt.now()
print("Without formatting", now)

# Example 1

s = now.strftime("%A %m %-Y")
print('\nExample 1:', s)

# Example 2

s = now.strftime("%a %-m %y")
print('\nExample 2:', s)

# Example 3

s = now.strftime("%-I %p %S")
print('\nExample 3:', s)

# Example 4

s = now.strftime("%H:%M:%S")
print('\nExample 4:', s)

Output

Without formatting 2021-08-19 18:16:25.881661

Example 1: Thursday 08 2021

Example 2: Thu 8 21

Example 3: 6 PM 25

Example 4: 18:16:25

Note: For more information, refer to strftime() method.

Python DateTime `strptime`

strptime() creates a datetime object from the given string.

Example: DateTime strptime

# import datetime module from datetime
from datetime import datetime
  
# consider the time stamps from a list  in string
# format DD/MM/YY H:M:S.micros
time_data = ["25/05/99 02:35:8.023", "26/05/99 12:45:0.003",
             "27/05/99 07:35:5.523", "28/05/99 05:15:55.523"]
  
# format the string in the given format : day/month/year 
# hours/minutes/seconds-micro seconds
format_data = "%d/%m/%y %H:%M:%S.%f"
  
# Using strptime with datetime we will format string
# into datetime
for i in time_data:
    print(datetime.strptime(i, format_data))

Output

1999-05-25 02:35:08.023000
1999-05-26 12:45:00.003000
1999-05-27 07:35:05.523000
1999-05-28 05:15:55.523000

Handling Python DateTime timezone

Timezones in DateTime can be used in the case where one might want to display time according to the timezone of a specific region. This can be done using the pytz module of Python. This module serves the date-time conversion functionalities and helps users serving international client bases.

from datetime import datetime
from pytz import timezone
 
format = "%Y-%m-%d %H:%M:%S %Z%z"
 
# Current time in UTC
now_utc = datetime.now(timezone('UTC'))
print(now_utc.strftime(format))
 
timezones = ['Asia/Kolkata', 'Europe/Kiev', 'America/New_York']
 
for tzone in timezones:
 
    # Convert to Asia/Kolkata time zone
    now_asia = now_utc.astimezone(timezone(tzone))
    print(now_asia.strftime(format))

Output

2021-08-19 18:27:28 UTC+0000
2021-08-19 23:57:28 IST+0530
2021-08-19 21:27:28 EEST+0300
2021-08-19 14:27:28 EDT-0400

py

datetime module

Date Output

Creating Date Objects

The strftime() Method

DateTime Module

Date class

List of Date class Methods

Time class

List of Time class Methods

Datetime class

List of Datetime Class Methods

Timedelta class

Operations supported by Timedelta Class

Format Datetime

Python Datetime strftime

Python DateTime strptime

Handling Python DateTime timezone

`datetime` module

The `strftime()` Method

Python DateTime `strptime`