Time, Date, Timestamp in Python

External

• https://docs.python.org/3/library/datetime.html

Internal

• Time
• Python Code Examples

Overview

The Standard Library datetime module provides datetime, date and time types. The datetime type combines information stored in data and time and it is the most commonly used. Additionally, the dateutil module provides useful extensions.

datetime Module

https://docs.python.org/3/library/datetime.html#module-datetime

https://geekflare.com/calculate-time-difference-in-python/

datetime Overview

The datetime module provides classes for manipulating dates and times. The datetime package documentation seems to recommend the dateutil for time zone support and parsing.

The datetime.datetime Type

datetime is an immutable type, so methods that seem to modify an instance actually return new instances. Given a datetime instances, the equivalent date and time type instances can be obtained with date(), respectively time().

Time Interval with timedelta

The difference of two datetime objects produce a datetime.timedelta type:

from datetime import datetime
dt1 = datetime(2022,3,27,13,10,45,46000) 
dt2 = datetime(2022,6,30,14,28) 
tdelta = dt2 - dt1 
print(tdelta) 
print(type(tdelta)) 
print(dt1.day) # prints 27
print(dt1.minute) # prints 10

To get the total number of seconds in timedelta, use total_seconds():

from datetime import datetime
t0 = datetime.now()
...
t1 = datetime.now()
print((t1 - t0).total_seconds())

now Time

from datetime import datetime

now = datetime.now()

current_time = now.strftime("%H:%M:%S")
print("Current Time =", current_time)

Current Date

With now():

from datetime import datetime
d = datetime.now().strftime("%Y-%m-%d")
print(d) # displays YYYY-mm-dd

With date.today():

from datetime import date
print(str(date.today())) # displays YYYY-mm-dd

Format

Parsing from String

from datetime import datetime
s = '12/31/2023'
d = datetime.strptime(s, "%m/%d/%Y")
assert d.year == 2023
assert d.month == 12
assert d.day == 31

The common timestamp elements are '%Y-%m-%d %H:%M:%S'.

ISO C89 compatible format specifications:

Type	Description
%Y	Four-digit year
%y	Two-digit year
%m	Two-digit month [01, 12]
%d	Two-digit day [01, 31]
%H	Hour (24-hour clock) [00, 23]
%I	Hour (12-hour clock) [01, 12]
%M	Two-digit minute [00, 59]
%S	Second [00, 61] (seconds 60, 61 account for leap seconds)
%f	Microsecond as an integer, zero-padded (from 000000 to 999999)
%j	Day of the year as a zero-padded integer (from 001 to 336)
%w	Weekday as an integer [0 (Sunday), 6]
%u	Weekday as an integer starting from 1, where 1 is Monday.
%U	Week number of the year [00, 53]; Sunday is considered the first day of the week, and days before the first Sunday of the year are “week 0”
%W	Week number of the year [00, 53]; Monday is considered the first day of the week, and days before the first Monday of the year are “week 0”
%z	UTC time zone offset as +HHMM or -HHMM; empty if time zone naive
%Z	Time zone name as a string, or empty string if no time zone
%F	Shortcut for %Y-%m-%d (e.g., 2012-4-18)
%D	Shortcut for %m/%d/%y (e.g., 04/18/12)

Also see Time, Date and Timestamp Parsing with dateutil below.

Formating as String

d = ...
d.strftime("%Y-%m-%d %H:%M")

Replace Time Fields

dt_hour = dt.replace(minute=0, second=0)

Since datetime is immutable, new instances will be generated.

dateutil Module

https://pypi.org/project/python-dateutil/

Time, Date and Timestamp Parsing with dateutil

The datetime package documentation seems to recommend the dateutil for time zone support and parsing.

import dateutil.parser as du

d = du.parse('10/01/2023')
assert d.year == 2023
assert d.month == 10
assert d.day == 1

time Module

Sleep

from time import sleep
sleep(1)